diff --git a/.circleci/config.yml b/.circleci/config.yml
index ca24f41a..bcf2e1d5 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -13,7 +13,7 @@ jobs:
           name: Test
           command: |
             ./tests/test-license.py
-            cc -v; CFLAGS="-O0 -Werror" make all && make clean
+            cc -v; CFLAGS="-O0 -Werror -pedantic" make all && make clean
             make c99build         ; make clean
             make c11build         ; make clean
             make aarch64build     ; make clean
diff --git a/lib/common/compiler.h b/lib/common/compiler.h
index 2f18efb0..95e94835 100644
--- a/lib/common/compiler.h
+++ b/lib/common/compiler.h
@@ -17,7 +17,7 @@
 /* force inlining */
 
 #if !defined(ZSTD_NO_INLINE)
-#if defined (__GNUC__) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
+#if (defined(__GNUC__) && !defined(__STRICT_ANSI__)) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
 #  define INLINE_KEYWORD inline
 #else
 #  define INLINE_KEYWORD
diff --git a/lib/common/fse_decompress.c b/lib/common/fse_decompress.c
index 9f948e1c..bcc2223c 100644
--- a/lib/common/fse_decompress.c
+++ b/lib/common/fse_decompress.c
@@ -262,7 +262,7 @@ size_t FSE_decompress_wksp(void* dst, size_t dstCapacity, const void* cSrc, size
     /* normal FSE decoding mode */
     size_t const NCountLength = FSE_readNCount (counting, &maxSymbolValue, &tableLog, istart, cSrcSize);
     if (FSE_isError(NCountLength)) return NCountLength;
-    //if (NCountLength >= cSrcSize) return ERROR(srcSize_wrong);   /* too small input size; supposed to be already checked in NCountLength, only remaining case : NCountLength==cSrcSize */
+    /* if (NCountLength >= cSrcSize) return ERROR(srcSize_wrong); */  /* too small input size; supposed to be already checked in NCountLength, only remaining case : NCountLength==cSrcSize */
     if (tableLog > maxLog) return ERROR(tableLog_tooLarge);
     ip += NCountLength;
     cSrcSize -= NCountLength;
diff --git a/lib/common/xxhash.c b/lib/common/xxhash.c
index 429a869e..72314c59 100644
--- a/lib/common/xxhash.c
+++ b/lib/common/xxhash.c
@@ -95,7 +95,7 @@ static void* XXH_memcpy(void* dest, const void* src, size_t size) { return memcp
 /* *************************************
 *  Compiler Specific Options
 ***************************************/
-#if defined (__GNUC__) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
+#if (defined(__GNUC__) && !defined(__STRICT_ANSI__)) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
 #  define INLINE_KEYWORD inline
 #else
 #  define INLINE_KEYWORD
diff --git a/lib/common/zstd_internal.h b/lib/common/zstd_internal.h
index 950b789c..57a6137e 100644
--- a/lib/common/zstd_internal.h
+++ b/lib/common/zstd_internal.h
@@ -53,6 +53,31 @@ extern "C" {
 #define MIN(a,b) ((a)<(b) ? (a) : (b))
 #define MAX(a,b) ((a)>(b) ? (a) : (b))
 
+/**
+ * Ignore: this is an internal helper.
+ *
+ * This is a helper function to help force C99-correctness during compilation.
+ * Under strict compilation modes, variadic macro arguments can't be empty.
+ * However, variadic function arguments can be. Using a function therefore lets
+ * us statically check that at least one (string) argument was passed,
+ * independent of the compilation flags.
+ */
+static INLINE_KEYWORD UNUSED_ATTR
+void _force_has_format_string(const char *format, ...) {
+  (void)format;
+}
+
+/**
+ * Ignore: this is an internal helper.
+ *
+ * We want to force this function invocation to be syntactically correct, but
+ * we don't want to force runtime evaluation of its arguments.
+ */
+#define _FORCE_HAS_FORMAT_STRING(...) \
+  if (0) { \
+    _force_has_format_string(__VA_ARGS__); \
+  }
+
 /**
  * Return the specified error if the condition evaluates to true.
  *
@@ -62,7 +87,9 @@ extern "C" {
  */
 #define RETURN_ERROR_IF(cond, err, ...) \
   if (cond) { \
-    RAWLOG(3, "%s:%d: ERROR!: check %s failed, returning %s", __FILE__, __LINE__, ZSTD_QUOTE(cond), ZSTD_QUOTE(ERROR(err))); \
+    RAWLOG(3, "%s:%d: ERROR!: check %s failed, returning %s", \
+           __FILE__, __LINE__, ZSTD_QUOTE(cond), ZSTD_QUOTE(ERROR(err))); \
+    _FORCE_HAS_FORMAT_STRING(__VA_ARGS__); \
     RAWLOG(3, ": " __VA_ARGS__); \
     RAWLOG(3, "\n"); \
     return ERROR(err); \
@@ -75,7 +102,9 @@ extern "C" {
  */
 #define RETURN_ERROR(err, ...) \
   do { \
-    RAWLOG(3, "%s:%d: ERROR!: unconditional check failed, returning %s", __FILE__, __LINE__, ZSTD_QUOTE(ERROR(err))); \
+    RAWLOG(3, "%s:%d: ERROR!: unconditional check failed, returning %s", \
+           __FILE__, __LINE__, ZSTD_QUOTE(ERROR(err))); \
+    _FORCE_HAS_FORMAT_STRING(__VA_ARGS__); \
     RAWLOG(3, ": " __VA_ARGS__); \
     RAWLOG(3, "\n"); \
     return ERROR(err); \
@@ -90,7 +119,9 @@ extern "C" {
   do { \
     size_t const err_code = (err); \
     if (ERR_isError(err_code)) { \
-      RAWLOG(3, "%s:%d: ERROR!: forwarding error in %s: %s", __FILE__, __LINE__, ZSTD_QUOTE(err), ERR_getErrorName(err_code)); \
+      RAWLOG(3, "%s:%d: ERROR!: forwarding error in %s: %s", \
+             __FILE__, __LINE__, ZSTD_QUOTE(err), ERR_getErrorName(err_code)); \
+      _FORCE_HAS_FORMAT_STRING(__VA_ARGS__); \
       RAWLOG(3, ": " __VA_ARGS__); \
       RAWLOG(3, "\n"); \
       return err_code; \
diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index d12a1e6f..22f5542e 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -235,7 +235,7 @@ size_t ZSTD_CCtxParams_reset(ZSTD_CCtx_params* params)
 }
 
 size_t ZSTD_CCtxParams_init(ZSTD_CCtx_params* cctxParams, int compressionLevel) {
-    RETURN_ERROR_IF(!cctxParams, GENERIC);
+    RETURN_ERROR_IF(!cctxParams, GENERIC, "NULL pointer!");
     memset(cctxParams, 0, sizeof(*cctxParams));
     cctxParams->compressionLevel = compressionLevel;
     cctxParams->fParams.contentSizeFlag = 1;
@@ -244,8 +244,8 @@ size_t ZSTD_CCtxParams_init(ZSTD_CCtx_params* cctxParams, int compressionLevel)
 
 size_t ZSTD_CCtxParams_init_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params)
 {
-    RETURN_ERROR_IF(!cctxParams, GENERIC);
-    FORWARD_IF_ERROR( ZSTD_checkCParams(params.cParams) );
+    RETURN_ERROR_IF(!cctxParams, GENERIC, "NULL pointer!");
+    FORWARD_IF_ERROR( ZSTD_checkCParams(params.cParams) , "");
     memset(cctxParams, 0, sizeof(*cctxParams));
     assert(!ZSTD_checkCParams(params.cParams));
     cctxParams->cParams = params.cParams;
@@ -441,7 +441,7 @@ static size_t ZSTD_cParam_clampBounds(ZSTD_cParameter cParam, int* value)
 
 #define BOUNDCHECK(cParam, val) { \
     RETURN_ERROR_IF(!ZSTD_cParam_withinBounds(cParam,val), \
-                    parameter_outOfBound); \
+                    parameter_outOfBound, "Param out of bounds"); \
 }
 
 
@@ -489,7 +489,7 @@ size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value)
         if (ZSTD_isUpdateAuthorized(param)) {
             cctx->cParamsChanged = 1;
         } else {
-            RETURN_ERROR(stage_wrong);
+            RETURN_ERROR(stage_wrong, "can only set params in ctx init stage");
     }   }
 
     switch(param)
@@ -526,7 +526,7 @@ size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value)
     case ZSTD_c_srcSizeHint:
         break;
 
-    default: RETURN_ERROR(parameter_unsupported);
+    default: RETURN_ERROR(parameter_unsupported, "unknown parameter");
     }
     return ZSTD_CCtxParams_setParameter(&cctx->requestedParams, param, value);
 }
@@ -543,7 +543,7 @@ size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* CCtxParams,
         return (size_t)CCtxParams->format;
 
     case ZSTD_c_compressionLevel : {
-        FORWARD_IF_ERROR(ZSTD_cParam_clampBounds(param, &value));
+        FORWARD_IF_ERROR(ZSTD_cParam_clampBounds(param, &value), "");
         if (value) {  /* 0 : does not change current level */
             CCtxParams->compressionLevel = value;
         }
@@ -631,7 +631,7 @@ size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* CCtxParams,
         RETURN_ERROR_IF(value!=0, parameter_unsupported, "not compiled with multithreading");
         return 0;
 #else
-        FORWARD_IF_ERROR(ZSTD_cParam_clampBounds(param, &value));
+        FORWARD_IF_ERROR(ZSTD_cParam_clampBounds(param, &value), "");
         CCtxParams->nbWorkers = value;
         return CCtxParams->nbWorkers;
 #endif
@@ -644,7 +644,7 @@ size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* CCtxParams,
         /* Adjust to the minimum non-default value. */
         if (value != 0 && value < ZSTDMT_JOBSIZE_MIN)
             value = ZSTDMT_JOBSIZE_MIN;
-        FORWARD_IF_ERROR(ZSTD_cParam_clampBounds(param, &value));
+        FORWARD_IF_ERROR(ZSTD_cParam_clampBounds(param, &value), "");
         assert(value >= 0);
         CCtxParams->jobSize = value;
         return CCtxParams->jobSize;
@@ -655,7 +655,7 @@ size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* CCtxParams,
         RETURN_ERROR_IF(value!=0, parameter_unsupported, "not compiled with multithreading");
         return 0;
 #else
-        FORWARD_IF_ERROR(ZSTD_cParam_clampBounds(ZSTD_c_overlapLog, &value));
+        FORWARD_IF_ERROR(ZSTD_cParam_clampBounds(ZSTD_c_overlapLog, &value), "");
         CCtxParams->overlapLog = value;
         return CCtxParams->overlapLog;
 #endif
@@ -665,7 +665,7 @@ size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* CCtxParams,
         RETURN_ERROR_IF(value!=0, parameter_unsupported, "not compiled with multithreading");
         return 0;
 #else
-        FORWARD_IF_ERROR(ZSTD_cParam_clampBounds(ZSTD_c_overlapLog, &value));
+        FORWARD_IF_ERROR(ZSTD_cParam_clampBounds(ZSTD_c_overlapLog, &value), "");
         CCtxParams->rsyncable = value;
         return CCtxParams->rsyncable;
 #endif
@@ -694,7 +694,7 @@ size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* CCtxParams,
 
     case ZSTD_c_ldmHashRateLog :
         RETURN_ERROR_IF(value > ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN,
-                        parameter_outOfBound);
+                        parameter_outOfBound, "Param out of bounds!");
         CCtxParams->ldmParams.hashRateLog = value;
         return CCtxParams->ldmParams.hashRateLog;
 
@@ -834,8 +834,11 @@ size_t ZSTD_CCtx_setParametersUsingCCtxParams(
         ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params)
 {
     DEBUGLOG(4, "ZSTD_CCtx_setParametersUsingCCtxParams");
-    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong);
-    RETURN_ERROR_IF(cctx->cdict, stage_wrong);
+    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
+                    "The context is in the wrong stage!");
+    RETURN_ERROR_IF(cctx->cdict, stage_wrong,
+                    "Can't override parameters with cdict attached (some must "
+                    "be inherited from the cdict).");
 
     cctx->requestedParams = *params;
     return 0;
@@ -844,7 +847,8 @@ size_t ZSTD_CCtx_setParametersUsingCCtxParams(
 ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize)
 {
     DEBUGLOG(4, "ZSTD_CCtx_setPledgedSrcSize to %u bytes", (U32)pledgedSrcSize);
-    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong);
+    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
+                    "Can't set pledgedSrcSize when not in init stage.");
     cctx->pledgedSrcSizePlusOne = pledgedSrcSize+1;
     return 0;
 }
@@ -882,7 +886,7 @@ static size_t ZSTD_initLocalDict(ZSTD_CCtx* cctx)
             dl->dictContentType,
             cParams,
             cctx->customMem);
-    RETURN_ERROR_IF(!dl->cdict, memory_allocation);
+    RETURN_ERROR_IF(!dl->cdict, memory_allocation, "ZSTD_createCDict_advanced failed");
     cctx->cdict = dl->cdict;
     return 0;
 }
@@ -891,7 +895,8 @@ size_t ZSTD_CCtx_loadDictionary_advanced(
         ZSTD_CCtx* cctx, const void* dict, size_t dictSize,
         ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType)
 {
-    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong);
+    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
+                    "Can't load a dictionary when ctx is not in init stage.");
     RETURN_ERROR_IF(cctx->staticSize, memory_allocation,
                     "no malloc for static CCtx");
     DEBUGLOG(4, "ZSTD_CCtx_loadDictionary_advanced (size: %u)", (U32)dictSize);
@@ -902,7 +907,7 @@ size_t ZSTD_CCtx_loadDictionary_advanced(
         cctx->localDict.dict = dict;
     } else {
         void* dictBuffer = ZSTD_malloc(dictSize, cctx->customMem);
-        RETURN_ERROR_IF(!dictBuffer, memory_allocation);
+        RETURN_ERROR_IF(!dictBuffer, memory_allocation, "NULL pointer!");
         memcpy(dictBuffer, dict, dictSize);
         cctx->localDict.dictBuffer = dictBuffer;
         cctx->localDict.dict = dictBuffer;
@@ -928,7 +933,8 @@ ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, s
 
 size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict)
 {
-    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong);
+    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
+                    "Can't ref a dict when ctx not in init stage.");
     /* Free the existing local cdict (if any) to save memory. */
     ZSTD_clearAllDicts(cctx);
     cctx->cdict = cdict;
@@ -943,7 +949,8 @@ size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSiz
 size_t ZSTD_CCtx_refPrefix_advanced(
         ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType)
 {
-    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong);
+    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
+                    "Can't ref a prefix when ctx not in init stage.");
     ZSTD_clearAllDicts(cctx);
     if (prefix != NULL && prefixSize > 0) {
         cctx->prefixDict.dict = prefix;
@@ -964,7 +971,8 @@ size_t ZSTD_CCtx_reset(ZSTD_CCtx* cctx, ZSTD_ResetDirective reset)
     }
     if ( (reset == ZSTD_reset_parameters)
       || (reset == ZSTD_reset_session_and_parameters) ) {
-        RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong);
+        RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
+                        "Can't reset parameters only when not in init stage.");
         ZSTD_clearAllDicts(cctx);
         return ZSTD_CCtxParams_reset(&cctx->requestedParams);
     }
@@ -1474,7 +1482,7 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
                 needsIndexReset = ZSTDirp_reset;
 
                 ZSTD_cwksp_free(ws, zc->customMem);
-                FORWARD_IF_ERROR(ZSTD_cwksp_create(ws, neededSpace, zc->customMem));
+                FORWARD_IF_ERROR(ZSTD_cwksp_create(ws, neededSpace, zc->customMem), "");
 
                 DEBUGLOG(5, "reserving object space");
                 /* Statically sized space.
@@ -1545,7 +1553,7 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
             &params.cParams,
             crp,
             needsIndexReset,
-            ZSTD_resetTarget_CCtx));
+            ZSTD_resetTarget_CCtx), "");
 
         /* ldm hash table */
         if (params.ldmParams.enableLdm) {
@@ -1623,7 +1631,7 @@ ZSTD_resetCCtx_byAttachingCDict(ZSTD_CCtx* cctx,
         params.cParams = ZSTD_adjustCParams_internal(*cdict_cParams, pledgedSrcSize, 0);
         params.cParams.windowLog = windowLog;
         FORWARD_IF_ERROR(ZSTD_resetCCtx_internal(cctx, params, pledgedSrcSize,
-                                                 ZSTDcrp_makeClean, zbuff));
+                                                 ZSTDcrp_makeClean, zbuff), "");
         assert(cctx->appliedParams.cParams.strategy == cdict_cParams->strategy);
     }
 
@@ -1672,7 +1680,7 @@ static size_t ZSTD_resetCCtx_byCopyingCDict(ZSTD_CCtx* cctx,
         params.cParams = *cdict_cParams;
         params.cParams.windowLog = windowLog;
         FORWARD_IF_ERROR(ZSTD_resetCCtx_internal(cctx, params, pledgedSrcSize,
-                                                 ZSTDcrp_leaveDirty, zbuff));
+                                                 ZSTDcrp_leaveDirty, zbuff), "");
         assert(cctx->appliedParams.cParams.strategy == cdict_cParams->strategy);
         assert(cctx->appliedParams.cParams.hashLog == cdict_cParams->hashLog);
         assert(cctx->appliedParams.cParams.chainLog == cdict_cParams->chainLog);
@@ -1753,7 +1761,8 @@ static size_t ZSTD_copyCCtx_internal(ZSTD_CCtx* dstCCtx,
                             ZSTD_buffered_policy_e zbuff)
 {
     DEBUGLOG(5, "ZSTD_copyCCtx_internal");
-    RETURN_ERROR_IF(srcCCtx->stage!=ZSTDcs_init, stage_wrong);
+    RETURN_ERROR_IF(srcCCtx->stage!=ZSTDcs_init, stage_wrong, 
+                    "Can't copy a ctx that's not in init stage.");
 
     memcpy(&dstCCtx->customMem, &srcCCtx->customMem, sizeof(ZSTD_customMem));
     {   ZSTD_CCtx_params params = dstCCtx->requestedParams;
@@ -1981,14 +1990,14 @@ ZSTD_compressSequences_internal(seqStore_t* seqStorePtr,
                                     literals, litSize,
                                     entropyWorkspace, entropyWkspSize,
                                     bmi2);
-        FORWARD_IF_ERROR(cSize);
+        FORWARD_IF_ERROR(cSize, "ZSTD_compressLiterals failed");
         assert(cSize <= dstCapacity);
         op += cSize;
     }
 
     /* Sequences Header */
     RETURN_ERROR_IF((oend-op) < 3 /*max nbSeq Size*/ + 1 /*seqHead*/,
-                    dstSize_tooSmall);
+                    dstSize_tooSmall, "Can't fit seq hdr in output buf!");
     if (nbSeq < 128) {
         *op++ = (BYTE)nbSeq;
     } else if (nbSeq < LONGNBSEQ) {
@@ -2033,7 +2042,7 @@ ZSTD_compressSequences_internal(seqStore_t* seqStorePtr,
                 prevEntropy->fse.litlengthCTable,
                 sizeof(prevEntropy->fse.litlengthCTable),
                 entropyWorkspace, entropyWkspSize);
-            FORWARD_IF_ERROR(countSize);
+            FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for LitLens failed");
             if (LLtype == set_compressed)
                 lastNCount = op;
             op += countSize;
@@ -2061,7 +2070,7 @@ ZSTD_compressSequences_internal(seqStore_t* seqStorePtr,
                 prevEntropy->fse.offcodeCTable,
                 sizeof(prevEntropy->fse.offcodeCTable),
                 entropyWorkspace, entropyWkspSize);
-            FORWARD_IF_ERROR(countSize);
+            FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for Offsets failed");
             if (Offtype == set_compressed)
                 lastNCount = op;
             op += countSize;
@@ -2087,7 +2096,7 @@ ZSTD_compressSequences_internal(seqStore_t* seqStorePtr,
                 prevEntropy->fse.matchlengthCTable,
                 sizeof(prevEntropy->fse.matchlengthCTable),
                 entropyWorkspace, entropyWkspSize);
-            FORWARD_IF_ERROR(countSize);
+            FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for MatchLengths failed");
             if (MLtype == set_compressed)
                 lastNCount = op;
             op += countSize;
@@ -2103,7 +2112,7 @@ ZSTD_compressSequences_internal(seqStore_t* seqStorePtr,
                                         CTable_LitLength, llCodeTable,
                                         sequences, nbSeq,
                                         longOffsets, bmi2);
-        FORWARD_IF_ERROR(bitstreamSize);
+        FORWARD_IF_ERROR(bitstreamSize, "ZSTD_encodeSequences failed");
         op += bitstreamSize;
         assert(op <= oend);
         /* zstd versions <= 1.3.4 mistakenly report corruption when
@@ -2147,7 +2156,7 @@ ZSTD_compressSequences(seqStore_t* seqStorePtr,
      */
     if ((cSize == ERROR(dstSize_tooSmall)) & (srcSize <= dstCapacity))
         return 0;  /* block not compressed */
-    FORWARD_IF_ERROR(cSize);
+    FORWARD_IF_ERROR(cSize, "ZSTD_compressSequences_internal failed");
 
     /* Check compressibility */
     {   size_t const maxCSize = srcSize - ZSTD_minGain(srcSize, cctxParams->cParams.strategy);
@@ -2273,7 +2282,7 @@ static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize)
             /* Updates ldmSeqStore.size */
             FORWARD_IF_ERROR(ZSTD_ldm_generateSequences(&zc->ldmState, &ldmSeqStore,
                                                &zc->appliedParams.ldmParams,
-                                               src, srcSize));
+                                               src, srcSize), "");
             /* Updates ldmSeqStore.pos */
             lastLLSize =
                 ZSTD_ldm_blockCompress(&ldmSeqStore,
@@ -2349,7 +2358,7 @@ size_t ZSTD_getSequences(ZSTD_CCtx* zc, ZSTD_Sequence* outSeqs,
     void* dst = ZSTD_malloc(dstCapacity, ZSTD_defaultCMem);
     SeqCollector seqCollector;
 
-    RETURN_ERROR_IF(dst == NULL, memory_allocation);
+    RETURN_ERROR_IF(dst == NULL, memory_allocation, "NULL pointer!");
 
     seqCollector.collectSequences = 1;
     seqCollector.seqStart = outSeqs;
@@ -2408,7 +2417,7 @@ static size_t ZSTD_compressBlock_internal(ZSTD_CCtx* zc,
                 (unsigned)zc->blockState.matchState.nextToUpdate);
 
     {   const size_t bss = ZSTD_buildSeqStore(zc, src, srcSize);
-        FORWARD_IF_ERROR(bss);
+        FORWARD_IF_ERROR(bss, "ZSTD_buildSeqStore failed");
         if (bss == ZSTDbss_noCompress) { cSize = 0; goto out; }
     }
 
@@ -2492,7 +2501,7 @@ static size_t ZSTD_compressBlock_targetCBlockSize_body(ZSTD_CCtx* zc,
             size_t const cSize = ZSTD_compressSuperBlock(zc, dst, dstCapacity, src, srcSize, lastBlock);
             if (cSize != ERROR(dstSize_tooSmall)) {
                 size_t const maxCSize = srcSize - ZSTD_minGain(srcSize, zc->appliedParams.cParams.strategy);
-                FORWARD_IF_ERROR(cSize);
+                FORWARD_IF_ERROR(cSize, "ZSTD_compressSuperBlock failed");
                 if (cSize != 0 && cSize < maxCSize + ZSTD_blockHeaderSize) {
                     ZSTD_confirmRepcodesAndEntropyTables(zc);
                     return cSize;
@@ -2517,10 +2526,10 @@ static size_t ZSTD_compressBlock_targetCBlockSize(ZSTD_CCtx* zc,
     const size_t bss = ZSTD_buildSeqStore(zc, src, srcSize);
     DEBUGLOG(5, "ZSTD_compressBlock_targetCBlockSize (dstCapacity=%u, dictLimit=%u, nextToUpdate=%u, srcSize=%zu)",
                 (unsigned)dstCapacity, (unsigned)zc->blockState.matchState.window.dictLimit, (unsigned)zc->blockState.matchState.nextToUpdate, srcSize);
-    FORWARD_IF_ERROR(bss);
+    FORWARD_IF_ERROR(bss, "ZSTD_buildSeqStore failed");
 
     cSize = ZSTD_compressBlock_targetCBlockSize_body(zc, dst, dstCapacity, src, srcSize, bss, lastBlock);
-    FORWARD_IF_ERROR(cSize);
+    FORWARD_IF_ERROR(cSize, "ZSTD_compressBlock_targetCBlockSize_body failed");
 
     if (zc->blockState.prevCBlock->entropy.fse.offcode_repeatMode == FSE_repeat_valid)
         zc->blockState.prevCBlock->entropy.fse.offcode_repeatMode = FSE_repeat_check;
@@ -2596,18 +2605,18 @@ static size_t ZSTD_compress_frameChunk (ZSTD_CCtx* cctx,
         {   size_t cSize;
             if (ZSTD_useTargetCBlockSize(&cctx->appliedParams)) {
                 cSize = ZSTD_compressBlock_targetCBlockSize(cctx, op, dstCapacity, ip, blockSize, lastBlock);
-                FORWARD_IF_ERROR(cSize);
+                FORWARD_IF_ERROR(cSize, "ZSTD_compressBlock_targetCBlockSize failed");
                 assert(cSize > 0);
                 assert(cSize <= blockSize + ZSTD_blockHeaderSize);
             } else {
                 cSize = ZSTD_compressBlock_internal(cctx,
                                         op+ZSTD_blockHeaderSize, dstCapacity-ZSTD_blockHeaderSize,
                                         ip, blockSize, 1 /* frame */);
-                FORWARD_IF_ERROR(cSize);
+                FORWARD_IF_ERROR(cSize, "ZSTD_compressBlock_internal failed");
 
                 if (cSize == 0) {  /* block is not compressible */
                     cSize = ZSTD_noCompressBlock(op, dstCapacity, ip, blockSize, lastBlock);
-                    FORWARD_IF_ERROR(cSize);
+                    FORWARD_IF_ERROR(cSize, "ZSTD_noCompressBlock failed");
                 } else {
                     U32 const cBlockHeader = cSize == 1 ?
                         lastBlock + (((U32)bt_rle)<<1) + (U32)(blockSize << 3) :
@@ -2649,7 +2658,8 @@ static size_t ZSTD_writeFrameHeader(void* dst, size_t dstCapacity,
     size_t pos=0;
 
     assert(!(params->fParams.contentSizeFlag && pledgedSrcSize == ZSTD_CONTENTSIZE_UNKNOWN));
-    RETURN_ERROR_IF(dstCapacity < ZSTD_FRAMEHEADERSIZE_MAX, dstSize_tooSmall);
+    RETURN_ERROR_IF(dstCapacity < ZSTD_FRAMEHEADERSIZE_MAX, dstSize_tooSmall,
+                    "dst buf is too small to fit worst-case frame header size.");
     DEBUGLOG(4, "ZSTD_writeFrameHeader : dictIDFlag : %u ; dictID : %u ; dictIDSizeCode : %u",
                 !params->fParams.noDictIDFlag, (unsigned)dictID, (unsigned)dictIDSizeCode);
 
@@ -2685,7 +2695,8 @@ static size_t ZSTD_writeFrameHeader(void* dst, size_t dstCapacity,
  */
 size_t ZSTD_writeLastEmptyBlock(void* dst, size_t dstCapacity)
 {
-    RETURN_ERROR_IF(dstCapacity < ZSTD_blockHeaderSize, dstSize_tooSmall);
+    RETURN_ERROR_IF(dstCapacity < ZSTD_blockHeaderSize, dstSize_tooSmall,
+                    "dst buf is too small to write frame trailer empty block.");
     {   U32 const cBlockHeader24 = 1 /*lastBlock*/ + (((U32)bt_raw)<<1);  /* 0 size */
         MEM_writeLE24(dst, cBlockHeader24);
         return ZSTD_blockHeaderSize;
@@ -2694,9 +2705,11 @@ size_t ZSTD_writeLastEmptyBlock(void* dst, size_t dstCapacity)
 
 size_t ZSTD_referenceExternalSequences(ZSTD_CCtx* cctx, rawSeq* seq, size_t nbSeq)
 {
-    RETURN_ERROR_IF(cctx->stage != ZSTDcs_init, stage_wrong);
+    RETURN_ERROR_IF(cctx->stage != ZSTDcs_init, stage_wrong,
+                    "wrong cctx stage");
     RETURN_ERROR_IF(cctx->appliedParams.ldmParams.enableLdm,
-                    parameter_unsupported);
+                    parameter_unsupported,
+                    "incompatible with ldm");
     cctx->externSeqStore.seq = seq;
     cctx->externSeqStore.size = nbSeq;
     cctx->externSeqStore.capacity = nbSeq;
@@ -2721,7 +2734,7 @@ static size_t ZSTD_compressContinue_internal (ZSTD_CCtx* cctx,
     if (frame && (cctx->stage==ZSTDcs_init)) {
         fhSize = ZSTD_writeFrameHeader(dst, dstCapacity, &cctx->appliedParams,
                                        cctx->pledgedSrcSizePlusOne-1, cctx->dictID);
-        FORWARD_IF_ERROR(fhSize);
+        FORWARD_IF_ERROR(fhSize, "ZSTD_writeFrameHeader failed");
         assert(fhSize <= dstCapacity);
         dstCapacity -= fhSize;
         dst = (char*)dst + fhSize;
@@ -2748,7 +2761,7 @@ static size_t ZSTD_compressContinue_internal (ZSTD_CCtx* cctx,
     {   size_t const cSize = frame ?
                              ZSTD_compress_frameChunk (cctx, dst, dstCapacity, src, srcSize, lastFrameChunk) :
                              ZSTD_compressBlock_internal (cctx, dst, dstCapacity, src, srcSize, 0 /* frame */);
-        FORWARD_IF_ERROR(cSize);
+        FORWARD_IF_ERROR(cSize, "%s", frame ? "ZSTD_compress_frameChunk failed" : "ZSTD_compressBlock_internal failed");
         cctx->consumedSrcSize += srcSize;
         cctx->producedCSize += (cSize + fhSize);
         assert(!(cctx->appliedParams.fParams.contentSizeFlag && cctx->pledgedSrcSizePlusOne == 0));
@@ -2785,7 +2798,7 @@ size_t ZSTD_compressBlock(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const
 {
     DEBUGLOG(5, "ZSTD_compressBlock: srcSize = %u", (unsigned)srcSize);
     { size_t const blockSizeMax = ZSTD_getBlockSize(cctx);
-      RETURN_ERROR_IF(srcSize > blockSizeMax, srcSize_wrong); }
+      RETURN_ERROR_IF(srcSize > blockSizeMax, srcSize_wrong, "input is larger than a block"); }
 
     return ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 0 /* frame mode */, 0 /* last chunk */);
 }
@@ -2868,9 +2881,9 @@ static size_t ZSTD_loadDictionaryContent(ZSTD_matchState_t* ms,
    NOTE: This behavior is not standard and could be improved in the future. */
 static size_t ZSTD_checkDictNCount(short* normalizedCounter, unsigned dictMaxSymbolValue, unsigned maxSymbolValue) {
     U32 s;
-    RETURN_ERROR_IF(dictMaxSymbolValue < maxSymbolValue, dictionary_corrupted);
+    RETURN_ERROR_IF(dictMaxSymbolValue < maxSymbolValue, dictionary_corrupted, "dict fse tables don't have all symbols");
     for (s = 0; s <= maxSymbolValue; ++s) {
-        RETURN_ERROR_IF(normalizedCounter[s] == 0, dictionary_corrupted);
+        RETURN_ERROR_IF(normalizedCounter[s] == 0, dictionary_corrupted, "dict fse tables don't have all symbols");
     }
     return 0;
 }
@@ -2894,56 +2907,56 @@ size_t ZSTD_loadCEntropy(ZSTD_compressedBlockState_t* bs, void* workspace,
         if (!hasZeroWeights)
             bs->entropy.huf.repeatMode = HUF_repeat_valid;
 
-        RETURN_ERROR_IF(HUF_isError(hufHeaderSize), dictionary_corrupted);
-        RETURN_ERROR_IF(maxSymbolValue < 255, dictionary_corrupted);
+        RETURN_ERROR_IF(HUF_isError(hufHeaderSize), dictionary_corrupted, "");
+        RETURN_ERROR_IF(maxSymbolValue < 255, dictionary_corrupted, "");
         dictPtr += hufHeaderSize;
     }
 
     {   unsigned offcodeLog;
         size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, offcodeMaxValue, &offcodeLog, dictPtr, dictEnd-dictPtr);
-        RETURN_ERROR_IF(FSE_isError(offcodeHeaderSize), dictionary_corrupted);
-        RETURN_ERROR_IF(offcodeLog > OffFSELog, dictionary_corrupted);
+        RETURN_ERROR_IF(FSE_isError(offcodeHeaderSize), dictionary_corrupted, "");
+        RETURN_ERROR_IF(offcodeLog > OffFSELog, dictionary_corrupted, "");
         /* Defer checking offcodeMaxValue because we need to know the size of the dictionary content */
         /* fill all offset symbols to avoid garbage at end of table */
         RETURN_ERROR_IF(FSE_isError(FSE_buildCTable_wksp(
                 bs->entropy.fse.offcodeCTable,
                 offcodeNCount, MaxOff, offcodeLog,
                 workspace, HUF_WORKSPACE_SIZE)),
-            dictionary_corrupted);
+            dictionary_corrupted, "");
         dictPtr += offcodeHeaderSize;
     }
 
     {   short matchlengthNCount[MaxML+1];
         unsigned matchlengthMaxValue = MaxML, matchlengthLog;
         size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, dictEnd-dictPtr);
-        RETURN_ERROR_IF(FSE_isError(matchlengthHeaderSize), dictionary_corrupted);
-        RETURN_ERROR_IF(matchlengthLog > MLFSELog, dictionary_corrupted);
+        RETURN_ERROR_IF(FSE_isError(matchlengthHeaderSize), dictionary_corrupted, "");
+        RETURN_ERROR_IF(matchlengthLog > MLFSELog, dictionary_corrupted, "");
         /* Every match length code must have non-zero probability */
-        FORWARD_IF_ERROR( ZSTD_checkDictNCount(matchlengthNCount, matchlengthMaxValue, MaxML));
+        FORWARD_IF_ERROR( ZSTD_checkDictNCount(matchlengthNCount, matchlengthMaxValue, MaxML), "");
         RETURN_ERROR_IF(FSE_isError(FSE_buildCTable_wksp(
                 bs->entropy.fse.matchlengthCTable,
                 matchlengthNCount, matchlengthMaxValue, matchlengthLog,
                 workspace, HUF_WORKSPACE_SIZE)),
-            dictionary_corrupted);
+            dictionary_corrupted, "");
         dictPtr += matchlengthHeaderSize;
     }
 
     {   short litlengthNCount[MaxLL+1];
         unsigned litlengthMaxValue = MaxLL, litlengthLog;
         size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, dictEnd-dictPtr);
-        RETURN_ERROR_IF(FSE_isError(litlengthHeaderSize), dictionary_corrupted);
-        RETURN_ERROR_IF(litlengthLog > LLFSELog, dictionary_corrupted);
+        RETURN_ERROR_IF(FSE_isError(litlengthHeaderSize), dictionary_corrupted, "");
+        RETURN_ERROR_IF(litlengthLog > LLFSELog, dictionary_corrupted, "");
         /* Every literal length code must have non-zero probability */
-        FORWARD_IF_ERROR( ZSTD_checkDictNCount(litlengthNCount, litlengthMaxValue, MaxLL));
+        FORWARD_IF_ERROR( ZSTD_checkDictNCount(litlengthNCount, litlengthMaxValue, MaxLL), "");
         RETURN_ERROR_IF(FSE_isError(FSE_buildCTable_wksp(
                 bs->entropy.fse.litlengthCTable,
                 litlengthNCount, litlengthMaxValue, litlengthLog,
                 workspace, HUF_WORKSPACE_SIZE)),
-            dictionary_corrupted);
+            dictionary_corrupted, "");
         dictPtr += litlengthHeaderSize;
     }
 
-    RETURN_ERROR_IF(dictPtr+12 > dictEnd, dictionary_corrupted);
+    RETURN_ERROR_IF(dictPtr+12 > dictEnd, dictionary_corrupted, "");
     bs->rep[0] = MEM_readLE32(dictPtr+0);
     bs->rep[1] = MEM_readLE32(dictPtr+4);
     bs->rep[2] = MEM_readLE32(dictPtr+8);
@@ -2982,7 +2995,7 @@ static size_t ZSTD_loadZstdDictionary(ZSTD_compressedBlockState_t* bs,
 
     dictID = params->fParams.noDictIDFlag ? 0 :  MEM_readLE32(dictPtr + 4 /* skip magic number */ );
     eSize = ZSTD_loadCEntropy(bs, workspace, offcodeNCount, &offcodeMaxValue, dict, dictSize);
-    FORWARD_IF_ERROR(eSize);
+    FORWARD_IF_ERROR(eSize, "ZSTD_loadCEntropy failed");
     dictPtr += eSize;
 
     {   size_t const dictContentSize = (size_t)(dictEnd - dictPtr);
@@ -2992,19 +3005,19 @@ static size_t ZSTD_loadZstdDictionary(ZSTD_compressedBlockState_t* bs,
             offcodeMax = ZSTD_highbit32(maxOffset); /* Calculate minimum offset code required to represent maxOffset */
         }
         /* All offset values <= dictContentSize + 128 KB must be representable */
-        FORWARD_IF_ERROR(ZSTD_checkDictNCount(offcodeNCount, offcodeMaxValue, MIN(offcodeMax, MaxOff)));
+        FORWARD_IF_ERROR(ZSTD_checkDictNCount(offcodeNCount, offcodeMaxValue, MIN(offcodeMax, MaxOff)), "");
         /* All repCodes must be <= dictContentSize and != 0*/
         {   U32 u;
             for (u=0; u<3; u++) {
-                RETURN_ERROR_IF(bs->rep[u] == 0, dictionary_corrupted);
-                RETURN_ERROR_IF(bs->rep[u] > dictContentSize, dictionary_corrupted);
+                RETURN_ERROR_IF(bs->rep[u] == 0, dictionary_corrupted, "");
+                RETURN_ERROR_IF(bs->rep[u] > dictContentSize, dictionary_corrupted, "");
         }   }
 
         bs->entropy.fse.offcode_repeatMode = FSE_repeat_valid;
         bs->entropy.fse.matchlength_repeatMode = FSE_repeat_valid;
         bs->entropy.fse.litlength_repeatMode = FSE_repeat_valid;
         FORWARD_IF_ERROR(ZSTD_loadDictionaryContent(
-            ms, NULL, ws, params, dictPtr, dictContentSize, dtlm));
+            ms, NULL, ws, params, dictPtr, dictContentSize, dtlm), "");
         return dictID;
     }
 }
@@ -3024,7 +3037,7 @@ ZSTD_compress_insertDictionary(ZSTD_compressedBlockState_t* bs,
 {
     DEBUGLOG(4, "ZSTD_compress_insertDictionary (dictSize=%u)", (U32)dictSize);
     if ((dict==NULL) || (dictSize<8)) {
-        RETURN_ERROR_IF(dictContentType == ZSTD_dct_fullDict, dictionary_wrong);
+        RETURN_ERROR_IF(dictContentType == ZSTD_dct_fullDict, dictionary_wrong, "");
         return 0;
     }
 
@@ -3040,7 +3053,7 @@ ZSTD_compress_insertDictionary(ZSTD_compressedBlockState_t* bs,
             return ZSTD_loadDictionaryContent(
                 ms, ls, ws, params, dict, dictSize, dtlm);
         }
-        RETURN_ERROR_IF(dictContentType == ZSTD_dct_fullDict, dictionary_wrong);
+        RETURN_ERROR_IF(dictContentType == ZSTD_dct_fullDict, dictionary_wrong, "");
         assert(0);   /* impossible */
     }
 
@@ -3077,7 +3090,7 @@ static size_t ZSTD_compressBegin_internal(ZSTD_CCtx* cctx,
     }
 
     FORWARD_IF_ERROR( ZSTD_resetCCtx_internal(cctx, *params, pledgedSrcSize,
-                                     ZSTDcrp_makeClean, zbuff) );
+                                     ZSTDcrp_makeClean, zbuff) , "");
     {   size_t const dictID = cdict ?
                 ZSTD_compress_insertDictionary(
                         cctx->blockState.prevCBlock, &cctx->blockState.matchState,
@@ -3088,7 +3101,7 @@ static size_t ZSTD_compressBegin_internal(ZSTD_CCtx* cctx,
                         cctx->blockState.prevCBlock, &cctx->blockState.matchState,
                         &cctx->ldmState, &cctx->workspace, &cctx->appliedParams, dict, dictSize,
                         dictContentType, dtlm, cctx->entropyWorkspace);
-        FORWARD_IF_ERROR(dictID);
+        FORWARD_IF_ERROR(dictID, "ZSTD_compress_insertDictionary failed");
         assert(dictID <= UINT_MAX);
         cctx->dictID = (U32)dictID;
     }
@@ -3105,7 +3118,7 @@ size_t ZSTD_compressBegin_advanced_internal(ZSTD_CCtx* cctx,
 {
     DEBUGLOG(4, "ZSTD_compressBegin_advanced_internal: wlog=%u", params->cParams.windowLog);
     /* compression parameters verification and optimization */
-    FORWARD_IF_ERROR( ZSTD_checkCParams(params->cParams) );
+    FORWARD_IF_ERROR( ZSTD_checkCParams(params->cParams) , "");
     return ZSTD_compressBegin_internal(cctx,
                                        dict, dictSize, dictContentType, dtlm,
                                        cdict,
@@ -3158,7 +3171,7 @@ static size_t ZSTD_writeEpilogue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity)
     /* special case : empty frame */
     if (cctx->stage == ZSTDcs_init) {
         fhSize = ZSTD_writeFrameHeader(dst, dstCapacity, &cctx->appliedParams, 0, 0);
-        FORWARD_IF_ERROR(fhSize);
+        FORWARD_IF_ERROR(fhSize, "ZSTD_writeFrameHeader failed");
         dstCapacity -= fhSize;
         op += fhSize;
         cctx->stage = ZSTDcs_ongoing;
@@ -3167,7 +3180,7 @@ static size_t ZSTD_writeEpilogue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity)
     if (cctx->stage != ZSTDcs_ending) {
         /* write one last empty block, make it the "last" block */
         U32 const cBlockHeader24 = 1 /* last block */ + (((U32)bt_raw)<<1) + 0;
-        RETURN_ERROR_IF(dstCapacity<4, dstSize_tooSmall);
+        RETURN_ERROR_IF(dstCapacity<4, dstSize_tooSmall, "no room for epilogue");
         MEM_writeLE32(op, cBlockHeader24);
         op += ZSTD_blockHeaderSize;
         dstCapacity -= ZSTD_blockHeaderSize;
@@ -3175,7 +3188,7 @@ static size_t ZSTD_writeEpilogue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity)
 
     if (cctx->appliedParams.fParams.checksumFlag) {
         U32 const checksum = (U32) XXH64_digest(&cctx->xxhState);
-        RETURN_ERROR_IF(dstCapacity<4, dstSize_tooSmall);
+        RETURN_ERROR_IF(dstCapacity<4, dstSize_tooSmall, "no room for checksum");
         DEBUGLOG(4, "ZSTD_writeEpilogue: write checksum : %08X", (unsigned)checksum);
         MEM_writeLE32(op, checksum);
         op += 4;
@@ -3193,9 +3206,9 @@ size_t ZSTD_compressEnd (ZSTD_CCtx* cctx,
     size_t const cSize = ZSTD_compressContinue_internal(cctx,
                                 dst, dstCapacity, src, srcSize,
                                 1 /* frame mode */, 1 /* last chunk */);
-    FORWARD_IF_ERROR(cSize);
+    FORWARD_IF_ERROR(cSize, "ZSTD_compressContinue_internal failed");
     endResult = ZSTD_writeEpilogue(cctx, (char*)dst + cSize, dstCapacity-cSize);
-    FORWARD_IF_ERROR(endResult);
+    FORWARD_IF_ERROR(endResult, "ZSTD_writeEpilogue failed");
     assert(!(cctx->appliedParams.fParams.contentSizeFlag && cctx->pledgedSrcSizePlusOne == 0));
     if (cctx->pledgedSrcSizePlusOne != 0) {  /* control src size */
         ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_UNKNOWN == (unsigned long long)-1);
@@ -3234,7 +3247,7 @@ size_t ZSTD_compress_advanced (ZSTD_CCtx* cctx,
                                ZSTD_parameters params)
 {
     DEBUGLOG(4, "ZSTD_compress_advanced");
-    FORWARD_IF_ERROR(ZSTD_checkCParams(params.cParams));
+    FORWARD_IF_ERROR(ZSTD_checkCParams(params.cParams), "");
     return ZSTD_compress_internal(cctx,
                                   dst, dstCapacity,
                                   src, srcSize,
@@ -3253,7 +3266,7 @@ size_t ZSTD_compress_advanced_internal(
     DEBUGLOG(4, "ZSTD_compress_advanced_internal (srcSize:%u)", (unsigned)srcSize);
     FORWARD_IF_ERROR( ZSTD_compressBegin_internal(cctx,
                          dict, dictSize, ZSTD_dct_auto, ZSTD_dtlm_fast, NULL,
-                         params, srcSize, ZSTDb_not_buffered) );
+                         params, srcSize, ZSTDb_not_buffered) , "");
     return ZSTD_compressEnd(cctx, dst, dstCapacity, src, srcSize);
 }
 
@@ -3337,7 +3350,7 @@ static size_t ZSTD_initCDict_internal(
         cdict->dictContent = dictBuffer;
     } else {
          void *internalBuffer = ZSTD_cwksp_reserve_object(&cdict->workspace, ZSTD_cwksp_align(dictSize, sizeof(void*)));
-        RETURN_ERROR_IF(!internalBuffer, memory_allocation);
+        RETURN_ERROR_IF(!internalBuffer, memory_allocation, "NULL pointer!");
         cdict->dictContent = internalBuffer;
         memcpy(internalBuffer, dictBuffer, dictSize);
     }
@@ -3354,7 +3367,7 @@ static size_t ZSTD_initCDict_internal(
         &cParams,
         ZSTDcrp_makeClean,
         ZSTDirp_reset,
-        ZSTD_resetTarget_CDict));
+        ZSTD_resetTarget_CDict), "");
     /* (Maybe) load the dictionary
      * Skips loading the dictionary if it is < 8 bytes.
      */
@@ -3367,7 +3380,7 @@ static size_t ZSTD_initCDict_internal(
                     &cdict->cBlockState, &cdict->matchState, NULL, &cdict->workspace,
                     &params, cdict->dictContent, cdict->dictContentSize,
                     dictContentType, ZSTD_dtlm_full, cdict->entropyWorkspace);
-            FORWARD_IF_ERROR(dictID);
+            FORWARD_IF_ERROR(dictID, "ZSTD_compress_insertDictionary failed");
             assert(dictID <= (size_t)(U32)-1);
             cdict->dictID = (U32)dictID;
         }
@@ -3515,7 +3528,7 @@ size_t ZSTD_compressBegin_usingCDict_advanced(
     ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize)
 {
     DEBUGLOG(4, "ZSTD_compressBegin_usingCDict_advanced");
-    RETURN_ERROR_IF(cdict==NULL, dictionary_wrong);
+    RETURN_ERROR_IF(cdict==NULL, dictionary_wrong, "NULL pointer!");
     {   ZSTD_CCtx_params params = cctx->requestedParams;
         params.cParams = ( pledgedSrcSize < ZSTD_USE_CDICT_PARAMS_SRCSIZE_CUTOFF
                         || pledgedSrcSize < cdict->dictContentSize * ZSTD_USE_CDICT_PARAMS_DICTSIZE_MULTIPLIER
@@ -3559,7 +3572,7 @@ size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx,
                                 const void* src, size_t srcSize,
                                 const ZSTD_CDict* cdict, ZSTD_frameParameters fParams)
 {
-    FORWARD_IF_ERROR(ZSTD_compressBegin_usingCDict_advanced(cctx, cdict, fParams, srcSize));   /* will check if cdict != NULL */
+    FORWARD_IF_ERROR(ZSTD_compressBegin_usingCDict_advanced(cctx, cdict, fParams, srcSize), "");   /* will check if cdict != NULL */
     return ZSTD_compressEnd(cctx, dst, dstCapacity, src, srcSize);
 }
 
@@ -3631,7 +3644,7 @@ static size_t ZSTD_resetCStream_internal(ZSTD_CStream* cctx,
                                          dict, dictSize, dictContentType, ZSTD_dtlm_fast,
                                          cdict,
                                          &params, pledgedSrcSize,
-                                         ZSTDb_buffered) );
+                                         ZSTDb_buffered) , "");
 
     cctx->inToCompress = 0;
     cctx->inBuffPos = 0;
@@ -3653,8 +3666,8 @@ size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pss)
      */
     U64 const pledgedSrcSize = (pss==0) ? ZSTD_CONTENTSIZE_UNKNOWN : pss;
     DEBUGLOG(4, "ZSTD_resetCStream: pledgedSrcSize = %u", (unsigned)pledgedSrcSize);
-    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) );
+    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) , "");
     return 0;
 }
 
@@ -3668,16 +3681,16 @@ size_t ZSTD_initCStream_internal(ZSTD_CStream* zcs,
                     unsigned long long pledgedSrcSize)
 {
     DEBUGLOG(4, "ZSTD_initCStream_internal");
-    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) );
+    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) , "");
     assert(!ZSTD_isError(ZSTD_checkCParams(params->cParams)));
     zcs->requestedParams = *params;
     assert(!((dict) && (cdict)));  /* either dict or cdict, not both */
     if (dict) {
-        FORWARD_IF_ERROR( ZSTD_CCtx_loadDictionary(zcs, dict, dictSize) );
+        FORWARD_IF_ERROR( ZSTD_CCtx_loadDictionary(zcs, dict, dictSize) , "");
     } else {
         /* Dictionary is cleared if !cdict */
-        FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, cdict) );
+        FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, cdict) , "");
     }
     return 0;
 }
@@ -3690,10 +3703,10 @@ size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs,
                                             unsigned long long pledgedSrcSize)
 {
     DEBUGLOG(4, "ZSTD_initCStream_usingCDict_advanced");
-    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) );
+    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) , "");
     zcs->requestedParams.fParams = fParams;
-    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, cdict) );
+    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, cdict) , "");
     return 0;
 }
 
@@ -3701,8 +3714,8 @@ size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs,
 size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict)
 {
     DEBUGLOG(4, "ZSTD_initCStream_usingCDict");
-    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, cdict) );
+    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, cdict) , "");
     return 0;
 }
 
@@ -3721,20 +3734,20 @@ size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
      */
     U64 const pledgedSrcSize = (pss==0 && params.fParams.contentSizeFlag==0) ? ZSTD_CONTENTSIZE_UNKNOWN : pss;
     DEBUGLOG(4, "ZSTD_initCStream_advanced");
-    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) );
-    FORWARD_IF_ERROR( ZSTD_checkCParams(params.cParams) );
+    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) , "");
+    FORWARD_IF_ERROR( ZSTD_checkCParams(params.cParams) , "");
     zcs->requestedParams = ZSTD_assignParamsToCCtxParams(&zcs->requestedParams, &params);
-    FORWARD_IF_ERROR( ZSTD_CCtx_loadDictionary(zcs, dict, dictSize) );
+    FORWARD_IF_ERROR( ZSTD_CCtx_loadDictionary(zcs, dict, dictSize) , "");
     return 0;
 }
 
 size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel)
 {
     DEBUGLOG(4, "ZSTD_initCStream_usingDict");
-    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_loadDictionary(zcs, dict, dictSize) );
+    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_loadDictionary(zcs, dict, dictSize) , "");
     return 0;
 }
 
@@ -3746,19 +3759,19 @@ size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigne
      */
     U64 const pledgedSrcSize = (pss==0) ? ZSTD_CONTENTSIZE_UNKNOWN : pss;
     DEBUGLOG(4, "ZSTD_initCStream_srcSize");
-    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, NULL) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) );
+    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, NULL) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) , "");
     return 0;
 }
 
 size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel)
 {
     DEBUGLOG(4, "ZSTD_initCStream");
-    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, NULL) );
-    FORWARD_IF_ERROR( ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel) );
+    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, NULL) , "");
+    FORWARD_IF_ERROR( ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel) , "");
     return 0;
 }
 
@@ -3811,7 +3824,7 @@ static size_t ZSTD_compressStream_generic(ZSTD_CStream* zcs,
                 size_t const cSize = ZSTD_compressEnd(zcs,
                                                 op, oend-op, ip, iend-ip);
                 DEBUGLOG(4, "ZSTD_compressEnd : cSize=%u", (unsigned)cSize);
-                FORWARD_IF_ERROR(cSize);
+                FORWARD_IF_ERROR(cSize, "ZSTD_compressEnd failed");
                 ip = iend;
                 op += cSize;
                 zcs->frameEnded = 1;
@@ -3853,7 +3866,7 @@ static size_t ZSTD_compressStream_generic(ZSTD_CStream* zcs,
                                     zcs->inBuff + zcs->inToCompress, iSize) :
                         ZSTD_compressContinue(zcs, cDst, oSize,
                                     zcs->inBuff + zcs->inToCompress, iSize);
-                FORWARD_IF_ERROR(cSize);
+                FORWARD_IF_ERROR(cSize, "%s", lastBlock ? "ZSTD_compressEnd failed" : "ZSTD_compressContinue failed");
                 zcs->frameEnded = lastBlock;
                 /* prepare next block */
                 zcs->inBuffTarget = zcs->inBuffPos + zcs->blockSize;
@@ -3930,7 +3943,7 @@ static size_t ZSTD_nextInputSizeHint_MTorST(const ZSTD_CCtx* cctx)
 
 size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
 {
-    FORWARD_IF_ERROR( ZSTD_compressStream2(zcs, output, input, ZSTD_e_continue) );
+    FORWARD_IF_ERROR( ZSTD_compressStream2(zcs, output, input, ZSTD_e_continue) , "");
     return ZSTD_nextInputSizeHint_MTorST(zcs);
 }
 
@@ -3942,15 +3955,15 @@ size_t ZSTD_compressStream2( ZSTD_CCtx* cctx,
 {
     DEBUGLOG(5, "ZSTD_compressStream2, endOp=%u ", (unsigned)endOp);
     /* check conditions */
-    RETURN_ERROR_IF(output->pos > output->size, GENERIC);
-    RETURN_ERROR_IF(input->pos  > input->size, GENERIC);
+    RETURN_ERROR_IF(output->pos > output->size, GENERIC, "invalid buffer");
+    RETURN_ERROR_IF(input->pos  > input->size, GENERIC, "invalid buffer");
     assert(cctx!=NULL);
 
     /* transparent initialization stage */
     if (cctx->streamStage == zcss_init) {
         ZSTD_CCtx_params params = cctx->requestedParams;
         ZSTD_prefixDict const prefixDict = cctx->prefixDict;
-        FORWARD_IF_ERROR( ZSTD_initLocalDict(cctx) ); /* Init the local dict if present. */
+        FORWARD_IF_ERROR( ZSTD_initLocalDict(cctx) , ""); /* Init the local dict if present. */
         memset(&cctx->prefixDict, 0, sizeof(cctx->prefixDict));   /* single usage */
         assert(prefixDict.dict==NULL || cctx->cdict==NULL);    /* only one can be set */
         DEBUGLOG(4, "ZSTD_compressStream2 : transparent init stage");
@@ -3969,14 +3982,14 @@ size_t ZSTD_compressStream2( ZSTD_CCtx* cctx,
                 DEBUGLOG(4, "ZSTD_compressStream2: creating new mtctx for nbWorkers=%u",
                             params.nbWorkers);
                 cctx->mtctx = ZSTDMT_createCCtx_advanced((U32)params.nbWorkers, cctx->customMem);
-                RETURN_ERROR_IF(cctx->mtctx == NULL, memory_allocation);
+                RETURN_ERROR_IF(cctx->mtctx == NULL, memory_allocation, "NULL pointer!");
             }
             /* mt compression */
             DEBUGLOG(4, "call ZSTDMT_initCStream_internal as nbWorkers=%u", params.nbWorkers);
             FORWARD_IF_ERROR( ZSTDMT_initCStream_internal(
                         cctx->mtctx,
                         prefixDict.dict, prefixDict.dictSize, prefixDict.dictContentType,
-                        cctx->cdict, params, cctx->pledgedSrcSizePlusOne-1) );
+                        cctx->cdict, params, cctx->pledgedSrcSizePlusOne-1) , "");
             cctx->streamStage = zcss_load;
             cctx->appliedParams.nbWorkers = params.nbWorkers;
         } else
@@ -3984,7 +3997,7 @@ size_t ZSTD_compressStream2( ZSTD_CCtx* cctx,
         {   FORWARD_IF_ERROR( ZSTD_resetCStream_internal(cctx,
                             prefixDict.dict, prefixDict.dictSize, prefixDict.dictContentType,
                             cctx->cdict,
-                            params, cctx->pledgedSrcSizePlusOne-1) );
+                            params, cctx->pledgedSrcSizePlusOne-1) , "");
             assert(cctx->streamStage == zcss_load);
             assert(cctx->appliedParams.nbWorkers == 0);
     }   }
@@ -4006,7 +4019,7 @@ size_t ZSTD_compressStream2( ZSTD_CCtx* cctx,
               || (endOp == ZSTD_e_end && flushMin == 0) ) { /* compression completed */
                 ZSTD_CCtx_reset(cctx, ZSTD_reset_session_only);
             }
-            FORWARD_IF_ERROR(flushMin);
+            FORWARD_IF_ERROR(flushMin, "ZSTDMT_compressStream_generic failed");
         } while (forceMaxProgress && flushMin != 0 && output->pos < output->size);
         DEBUGLOG(5, "completed ZSTD_compressStream2 delegating to ZSTDMT_compressStream_generic");
         /* Either we don't require maximum forward progress, we've finished the
@@ -4016,7 +4029,7 @@ size_t ZSTD_compressStream2( ZSTD_CCtx* cctx,
         return flushMin;
     }
 #endif
-    FORWARD_IF_ERROR( ZSTD_compressStream_generic(cctx, output, input, endOp) );
+    FORWARD_IF_ERROR( ZSTD_compressStream_generic(cctx, output, input, endOp) , "");
     DEBUGLOG(5, "completed ZSTD_compressStream2");
     return cctx->outBuffContentSize - cctx->outBuffFlushedSize; /* remaining to flush */
 }
@@ -4047,10 +4060,10 @@ size_t ZSTD_compress2(ZSTD_CCtx* cctx,
                                         dst, dstCapacity, &oPos,
                                         src, srcSize, &iPos,
                                         ZSTD_e_end);
-        FORWARD_IF_ERROR(result);
+        FORWARD_IF_ERROR(result, "ZSTD_compressStream2_simpleArgs failed");
         if (result != 0) {  /* compression not completed, due to lack of output space */
             assert(oPos == dstCapacity);
-            RETURN_ERROR(dstSize_tooSmall);
+            RETURN_ERROR(dstSize_tooSmall, "");
         }
         assert(iPos == srcSize);   /* all input is expected consumed */
         return oPos;
@@ -4072,7 +4085,7 @@ size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output)
 {
     ZSTD_inBuffer input = { NULL, 0, 0 };
     size_t const remainingToFlush = ZSTD_compressStream2(zcs, output, &input, ZSTD_e_end);
-    FORWARD_IF_ERROR( remainingToFlush );
+    FORWARD_IF_ERROR( remainingToFlush , "ZSTD_compressStream2 failed");
     if (zcs->appliedParams.nbWorkers > 0) return remainingToFlush;   /* minimal estimation */
     /* single thread mode : attempt to calculate remaining to flush more precisely */
     {   size_t const lastBlockSize = zcs->frameEnded ? 0 : ZSTD_BLOCKHEADERSIZE;
diff --git a/lib/compress/zstd_compress_internal.h b/lib/compress/zstd_compress_internal.h
index db7b89ce..d95eb1bf 100644
--- a/lib/compress/zstd_compress_internal.h
+++ b/lib/compress/zstd_compress_internal.h
@@ -370,7 +370,7 @@ MEM_STATIC size_t ZSTD_noCompressBlock (void* dst, size_t dstCapacity, const voi
 {
     U32 const cBlockHeader24 = lastBlock + (((U32)bt_raw)<<1) + (U32)(srcSize << 3);
     RETURN_ERROR_IF(srcSize + ZSTD_blockHeaderSize > dstCapacity,
-                    dstSize_tooSmall);
+                    dstSize_tooSmall, "dst buf too small for uncompressed block");
     MEM_writeLE24(dst, cBlockHeader24);
     memcpy((BYTE*)dst + ZSTD_blockHeaderSize, src, srcSize);
     return ZSTD_blockHeaderSize + srcSize;
@@ -954,7 +954,7 @@ MEM_STATIC U32 ZSTD_window_update(ZSTD_window_t* window,
         window->dictLimit = (U32)distanceFromBase;
         window->dictBase = window->base;
         window->base = ip - distanceFromBase;
-        // ms->nextToUpdate = window->dictLimit;
+        /* ms->nextToUpdate = window->dictLimit; */
         if (window->dictLimit - window->lowLimit < HASH_READ_SIZE) window->lowLimit = window->dictLimit;   /* too small extDict */
         contiguous = 0;
     }
diff --git a/lib/compress/zstd_compress_literals.c b/lib/compress/zstd_compress_literals.c
index b7680004..17e7168d 100644
--- a/lib/compress/zstd_compress_literals.c
+++ b/lib/compress/zstd_compress_literals.c
@@ -18,7 +18,7 @@ size_t ZSTD_noCompressLiterals (void* dst, size_t dstCapacity, const void* src,
     BYTE* const ostart = (BYTE* const)dst;
     U32   const flSize = 1 + (srcSize>31) + (srcSize>4095);
 
-    RETURN_ERROR_IF(srcSize + flSize > dstCapacity, dstSize_tooSmall);
+    RETURN_ERROR_IF(srcSize + flSize > dstCapacity, dstSize_tooSmall, "");
 
     switch(flSize)
     {
diff --git a/lib/compress/zstd_compress_sequences.c b/lib/compress/zstd_compress_sequences.c
index 07a03c8a..23a5f353 100644
--- a/lib/compress/zstd_compress_sequences.c
+++ b/lib/compress/zstd_compress_sequences.c
@@ -60,7 +60,7 @@ static size_t ZSTD_NCountCost(unsigned const* count, unsigned const max,
     BYTE wksp[FSE_NCOUNTBOUND];
     S16 norm[MaxSeq + 1];
     const U32 tableLog = FSE_optimalTableLog(FSELog, nbSeq, max);
-    FORWARD_IF_ERROR(FSE_normalizeCount(norm, tableLog, count, nbSeq, max));
+    FORWARD_IF_ERROR(FSE_normalizeCount(norm, tableLog, count, nbSeq, max), "");
     return FSE_writeNCount(wksp, sizeof(wksp), norm, max, tableLog);
 }
 
@@ -234,15 +234,15 @@ ZSTD_buildCTable(void* dst, size_t dstCapacity,
 
     switch (type) {
     case set_rle:
-        FORWARD_IF_ERROR(FSE_buildCTable_rle(nextCTable, (BYTE)max));
-        RETURN_ERROR_IF(dstCapacity==0, dstSize_tooSmall);
+        FORWARD_IF_ERROR(FSE_buildCTable_rle(nextCTable, (BYTE)max), "");
+        RETURN_ERROR_IF(dstCapacity==0, dstSize_tooSmall, "not enough space");
         *op = codeTable[0];
         return 1;
     case set_repeat:
         memcpy(nextCTable, prevCTable, prevCTableSize);
         return 0;
     case set_basic:
-        FORWARD_IF_ERROR(FSE_buildCTable_wksp(nextCTable, defaultNorm, defaultMax, defaultNormLog, entropyWorkspace, entropyWorkspaceSize));  /* note : could be pre-calculated */
+        FORWARD_IF_ERROR(FSE_buildCTable_wksp(nextCTable, defaultNorm, defaultMax, defaultNormLog, entropyWorkspace, entropyWorkspaceSize), "");  /* note : could be pre-calculated */
         return 0;
     case set_compressed: {
         S16 norm[MaxSeq + 1];
@@ -253,14 +253,14 @@ ZSTD_buildCTable(void* dst, size_t dstCapacity,
             nbSeq_1--;
         }
         assert(nbSeq_1 > 1);
-        FORWARD_IF_ERROR(FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max));
+        FORWARD_IF_ERROR(FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max), "");
         {   size_t const NCountSize = FSE_writeNCount(op, oend - op, norm, max, tableLog);   /* overflow protected */
-            FORWARD_IF_ERROR(NCountSize);
-            FORWARD_IF_ERROR(FSE_buildCTable_wksp(nextCTable, norm, max, tableLog, entropyWorkspace, entropyWorkspaceSize));
+            FORWARD_IF_ERROR(NCountSize, "FSE_writeNCount failed");
+            FORWARD_IF_ERROR(FSE_buildCTable_wksp(nextCTable, norm, max, tableLog, entropyWorkspace, entropyWorkspaceSize), "");
             return NCountSize;
         }
     }
-    default: assert(0); RETURN_ERROR(GENERIC);
+    default: assert(0); RETURN_ERROR(GENERIC, "impossible to reach");
     }
 }
 
diff --git a/lib/compress/zstd_compress_superblock.c b/lib/compress/zstd_compress_superblock.c
index fd475dcc..e44a14b6 100644
--- a/lib/compress/zstd_compress_superblock.c
+++ b/lib/compress/zstd_compress_superblock.c
@@ -28,7 +28,7 @@
  *  This metadata is populated in ZSTD_buildSuperBlockEntropy_literal() */
 typedef struct {
     symbolEncodingType_e hType;
-    BYTE hufDesBuffer[500]; // TODO give name to this value
+    BYTE hufDesBuffer[500]; /* TODO give name to this value */
     size_t hufDesSize;
 } ZSTD_hufCTablesMetadata_t;
 
@@ -41,9 +41,9 @@ typedef struct {
     symbolEncodingType_e llType;
     symbolEncodingType_e ofType;
     symbolEncodingType_e mlType;
-    BYTE fseTablesBuffer[500]; // TODO give name to this value
+    BYTE fseTablesBuffer[500]; /* TODO give name to this value */
     size_t fseTablesSize;
-    size_t lastCountSize; // This is to account for bug in 1.3.4. More detail in ZSTD_compressSubBlock_sequences()
+    size_t lastCountSize; /* This is to account for bug in 1.3.4. More detail in ZSTD_compressSubBlock_sequences() */
 } ZSTD_fseCTablesMetadata_t;
 
 typedef struct {
@@ -98,7 +98,7 @@ static size_t ZSTD_buildSuperBlockEntropy_literal(void* const src, size_t srcSiz
 
     /* Scan input and build symbol stats */
     {   size_t const largest = HIST_count_wksp (countWksp, &maxSymbolValue, (const BYTE*)src, srcSize, workspace, wkspSize);
-        FORWARD_IF_ERROR(largest);
+        FORWARD_IF_ERROR(largest, "HIST_count_wksp failed");
         if (largest == srcSize) {
             DEBUGLOG(5, "set_rle");
             hufMetadata->hType = set_rle;
@@ -122,7 +122,7 @@ static size_t ZSTD_buildSuperBlockEntropy_literal(void* const src, size_t srcSiz
     {   size_t const maxBits = HUF_buildCTable_wksp((HUF_CElt*)nextHuf->CTable, countWksp,
                                                     maxSymbolValue, huffLog,
                                                     nodeWksp, nodeWkspSize);
-        FORWARD_IF_ERROR(maxBits);
+        FORWARD_IF_ERROR(maxBits, "HUF_buildCTable_wksp");
         huffLog = (U32)maxBits;
         {   /* Build and write the CTable */
             size_t const newCSize = HUF_estimateCompressedSize(
@@ -209,7 +209,7 @@ static size_t ZSTD_buildSuperBlockEntropy_sequences(seqStore_t* seqStorePtr,
                                                     countWksp, max, llCodeTable, nbSeq, LL_defaultNorm, LL_defaultNormLog, MaxLL,
                                                     prevEntropy->litlengthCTable, sizeof(prevEntropy->litlengthCTable),
                                                     cTableWksp, cTableWkspSize);
-            FORWARD_IF_ERROR(countSize);
+            FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for LitLens failed");
             if (LLtype == set_compressed)
                 fseMetadata->lastCountSize = countSize;
             op += countSize;
@@ -233,7 +233,7 @@ static size_t ZSTD_buildSuperBlockEntropy_sequences(seqStore_t* seqStorePtr,
                                                     countWksp, max, ofCodeTable, nbSeq, OF_defaultNorm, OF_defaultNormLog, DefaultMaxOff,
                                                     prevEntropy->offcodeCTable, sizeof(prevEntropy->offcodeCTable),
                                                     cTableWksp, cTableWkspSize);
-            FORWARD_IF_ERROR(countSize);
+            FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for Offsets failed");
             if (Offtype == set_compressed)
                 fseMetadata->lastCountSize = countSize;
             op += countSize;
@@ -255,7 +255,7 @@ static size_t ZSTD_buildSuperBlockEntropy_sequences(seqStore_t* seqStorePtr,
                                                     countWksp, max, mlCodeTable, nbSeq, ML_defaultNorm, ML_defaultNormLog, MaxML,
                                                     prevEntropy->matchlengthCTable, sizeof(prevEntropy->matchlengthCTable),
                                                     cTableWksp, cTableWkspSize);
-            FORWARD_IF_ERROR(countSize);
+            FORWARD_IF_ERROR(countSize, "ZSTD_buildCTable for MatchLengths failed");
             if (MLtype == set_compressed)
                 fseMetadata->lastCountSize = countSize;
             op += countSize;
@@ -285,14 +285,14 @@ ZSTD_buildSuperBlockEntropy(seqStore_t* seqStorePtr,
                                             &entropyMetadata->hufMetadata,
                                             ZSTD_disableLiteralsCompression(cctxParams),
                                             workspace, wkspSize);
-    FORWARD_IF_ERROR(entropyMetadata->hufMetadata.hufDesSize);
+    FORWARD_IF_ERROR(entropyMetadata->hufMetadata.hufDesSize, "ZSTD_buildSuperBlockEntropy_literal failed");
     entropyMetadata->fseMetadata.fseTablesSize =
         ZSTD_buildSuperBlockEntropy_sequences(seqStorePtr,
                                               &prevEntropy->fse, &nextEntropy->fse,
                                               cctxParams,
                                               &entropyMetadata->fseMetadata,
                                               workspace, wkspSize);
-    FORWARD_IF_ERROR(entropyMetadata->fseMetadata.fseTablesSize);
+    FORWARD_IF_ERROR(entropyMetadata->fseMetadata.fseTablesSize, "ZSTD_buildSuperBlockEntropy_sequences failed");
     return 0;
 }
 
@@ -330,7 +330,7 @@ static size_t ZSTD_compressSubBlock_literal(const HUF_CElt* hufTable,
     symbolEncodingType_e hType = writeEntropy ? hufMetadata->hType : set_repeat;
     size_t cLitSize = 0;
 
-    (void)bmi2; // TODO bmi2...
+    (void)bmi2; /* TODO bmi2... */
 
     DEBUGLOG(5, "ZSTD_compressSubBlock_literal (litSize=%zu, lhSize=%zu, writeEntropy=%d)", litSize, lhSize, writeEntropy);
 
@@ -353,7 +353,7 @@ static size_t ZSTD_compressSubBlock_literal(const HUF_CElt* hufTable,
         DEBUGLOG(5, "ZSTD_compressSubBlock_literal (hSize=%zu)", hufMetadata->hufDesSize);
     }
 
-    // TODO bmi2
+    /* TODO bmi2 */
     {   const size_t cSize = singleStream ? HUF_compress1X_usingCTable(op, oend-op, literals, litSize, hufTable)
                                           : HUF_compress4X_usingCTable(op, oend-op, literals, litSize, hufTable);
         op += cSize;
@@ -451,7 +451,7 @@ static size_t ZSTD_compressSubBlock_sequences(const ZSTD_fseCTables_t* fseTables
     *entropyWritten = 0;
     /* Sequences Header */
     RETURN_ERROR_IF((oend-op) < 3 /*max nbSeq Size*/ + 1 /*seqHead*/,
-                    dstSize_tooSmall);
+                    dstSize_tooSmall, "");
     if (nbSeq < 0x7F)
         *op++ = (BYTE)nbSeq;
     else if (nbSeq < LONGNBSEQ)
@@ -487,7 +487,7 @@ static size_t ZSTD_compressSubBlock_sequences(const ZSTD_fseCTables_t* fseTables
                                         fseTables->litlengthCTable, llCode,
                                         sequences, nbSeq,
                                         longOffsets, bmi2);
-        FORWARD_IF_ERROR(bitstreamSize);
+        FORWARD_IF_ERROR(bitstreamSize, "ZSTD_encodeSequences failed");
         op += bitstreamSize;
         /* zstd versions <= 1.3.4 mistakenly report corruption when
          * FSE_readNCount() receives a buffer < 4 bytes.
@@ -552,7 +552,7 @@ static size_t ZSTD_compressSubBlock(const ZSTD_entropyCTables_t* entropy,
     {   size_t cLitSize = ZSTD_compressSubBlock_literal((const HUF_CElt*)entropy->huf.CTable,
                                                         &entropyMetadata->hufMetadata, literals, litSize,
                                                         op, oend-op, bmi2, writeLitEntropy, litEntropyWritten);
-        FORWARD_IF_ERROR(cLitSize);
+        FORWARD_IF_ERROR(cLitSize, "ZSTD_compressSubBlock_literal failed");
         if (cLitSize == 0) return 0;
         op += cLitSize;
     }
@@ -563,7 +563,7 @@ static size_t ZSTD_compressSubBlock(const ZSTD_entropyCTables_t* entropy,
                                                   cctxParams,
                                                   op, oend-op,
                                                   bmi2, writeSeqEntropy, seqEntropyWritten);
-        FORWARD_IF_ERROR(cSeqSize);
+        FORWARD_IF_ERROR(cSeqSize, "ZSTD_compressSubBlock_sequences failed");
         if (cSeqSize == 0) return 0;
         op += cSeqSize;
     }
@@ -764,8 +764,7 @@ static size_t ZSTD_compressSubBlock_multi(const seqStore_t* seqStorePtr,
                                                        bmi2, writeLitEntropy, writeSeqEntropy,
                                                        &litEntropyWritten, &seqEntropyWritten,
                                                        lastBlock && lastSequence);
-            FORWARD_IF_ERROR(cSize);
-            DEBUGLOG(5, "cSize = %zu | decompressedSize = %zu", cSize, decompressedSize);
+            FORWARD_IF_ERROR(cSize, "ZSTD_compressSubBlock failed");
             if (cSize > 0 && cSize < decompressedSize) {
                 DEBUGLOG(5, "Committed the sub-block");
                 assert(ip + decompressedSize <= iend);
@@ -802,7 +801,7 @@ static size_t ZSTD_compressSubBlock_multi(const seqStore_t* seqStorePtr,
     if (ip < iend) {
         size_t const cSize = ZSTD_noCompressBlock(op, oend - op, ip, iend - ip, lastBlock);
         DEBUGLOG(5, "ZSTD_compressSubBlock_multi last sub-block uncompressed, %zu bytes", (size_t)(iend - ip));
-        FORWARD_IF_ERROR(cSize);
+        FORWARD_IF_ERROR(cSize, "ZSTD_noCompressBlock failed");
         assert(cSize != 0);
         op += cSize;
         /* We have to regenerate the repcodes because we've skipped some sequences */
@@ -831,7 +830,7 @@ size_t ZSTD_compressSuperBlock(ZSTD_CCtx* zc,
           &zc->blockState.nextCBlock->entropy,
           &zc->appliedParams,
           &entropyMetadata,
-          zc->entropyWorkspace, HUF_WORKSPACE_SIZE /* statically allocated in resetCCtx */));
+          zc->entropyWorkspace, HUF_WORKSPACE_SIZE /* statically allocated in resetCCtx */), "");
 
     return ZSTD_compressSubBlock_multi(&zc->seqStore,
             zc->blockState.prevCBlock,
diff --git a/lib/compress/zstd_cwksp.h b/lib/compress/zstd_cwksp.h
index 5886893d..91f812fa 100644
--- a/lib/compress/zstd_cwksp.h
+++ b/lib/compress/zstd_cwksp.h
@@ -458,7 +458,7 @@ MEM_STATIC void ZSTD_cwksp_init(ZSTD_cwksp* ws, void* start, size_t size) {
 MEM_STATIC size_t ZSTD_cwksp_create(ZSTD_cwksp* ws, size_t size, ZSTD_customMem customMem) {
     void* workspace = ZSTD_malloc(size, customMem);
     DEBUGLOG(4, "cwksp: creating new workspace with %zd bytes", size);
-    RETURN_ERROR_IF(workspace == NULL, memory_allocation);
+    RETURN_ERROR_IF(workspace == NULL, memory_allocation, "NULL pointer!");
     ZSTD_cwksp_init(ws, workspace, size);
     return 0;
 }
diff --git a/lib/compress/zstd_opt.c b/lib/compress/zstd_opt.c
index 8d630196..890ae924 100644
--- a/lib/compress/zstd_opt.c
+++ b/lib/compress/zstd_opt.c
@@ -781,7 +781,7 @@ listStats(const U32* table, int lastEltID)
     int enb;
     for (enb=0; enb < nbElts; enb++) {
         (void)table;
-        //RAWLOG(2, "%3i:%3i,  ", enb, table[enb]);
+        /* RAWLOG(2, "%3i:%3i,  ", enb, table[enb]); */
         RAWLOG(2, "%4i,", table[enb]);
     }
     RAWLOG(2, " \n");
diff --git a/lib/compress/zstdmt_compress.c b/lib/compress/zstdmt_compress.c
index 12ebcd2b..56186f50 100644
--- a/lib/compress/zstdmt_compress.c
+++ b/lib/compress/zstdmt_compress.c
@@ -1063,7 +1063,7 @@ static ZSTD_CCtx_params ZSTDMT_initJobCCtxParams(const ZSTD_CCtx_params* params)
 static size_t ZSTDMT_resize(ZSTDMT_CCtx* mtctx, unsigned nbWorkers)
 {
     if (POOL_resize(mtctx->factory, nbWorkers)) return ERROR(memory_allocation);
-    FORWARD_IF_ERROR( ZSTDMT_expandJobsTable(mtctx, nbWorkers) );
+    FORWARD_IF_ERROR( ZSTDMT_expandJobsTable(mtctx, nbWorkers) , "");
     mtctx->bufPool = ZSTDMT_expandBufferPool(mtctx->bufPool, nbWorkers);
     if (mtctx->bufPool == NULL) return ERROR(memory_allocation);
     mtctx->cctxPool = ZSTDMT_expandCCtxPool(mtctx->cctxPool, nbWorkers);
@@ -1279,7 +1279,7 @@ static size_t ZSTDMT_compress_advanced_internal(
     if (ZSTDMT_serialState_reset(&mtctx->serial, mtctx->seqPool, params, avgJobSize, NULL, 0))
         return ERROR(memory_allocation);
 
-    FORWARD_IF_ERROR( ZSTDMT_expandJobsTable(mtctx, nbJobs) );  /* only expands if necessary */
+    FORWARD_IF_ERROR( ZSTDMT_expandJobsTable(mtctx, nbJobs) , "");  /* only expands if necessary */
 
     {   unsigned u;
         for (u=0; u<nbJobs; u++) {
@@ -1412,7 +1412,7 @@ size_t ZSTDMT_initCStream_internal(
 
     /* init */
     if (params.nbWorkers != mtctx->params.nbWorkers)
-        FORWARD_IF_ERROR( ZSTDMT_resize(mtctx, params.nbWorkers) );
+        FORWARD_IF_ERROR( ZSTDMT_resize(mtctx, params.nbWorkers) , "");
 
     if (params.jobSize != 0 && params.jobSize < ZSTDMT_JOBSIZE_MIN) params.jobSize = ZSTDMT_JOBSIZE_MIN;
     if (params.jobSize > (size_t)ZSTDMT_JOBSIZE_MAX) params.jobSize = (size_t)ZSTDMT_JOBSIZE_MAX;
@@ -2071,7 +2071,7 @@ size_t ZSTDMT_compressStream_generic(ZSTDMT_CCtx* mtctx,
       || ((endOp == ZSTD_e_end) && (!mtctx->frameEnded)) ) {   /* must finish the frame with a zero-size block */
         size_t const jobSize = mtctx->inBuff.filled;
         assert(mtctx->inBuff.filled <= mtctx->targetSectionSize);
-        FORWARD_IF_ERROR( ZSTDMT_createCompressionJob(mtctx, jobSize, endOp) );
+        FORWARD_IF_ERROR( ZSTDMT_createCompressionJob(mtctx, jobSize, endOp) , "");
     }
 
     /* check for potential compressed data ready to be flushed */
@@ -2085,7 +2085,7 @@ size_t ZSTDMT_compressStream_generic(ZSTDMT_CCtx* mtctx,
 
 size_t ZSTDMT_compressStream(ZSTDMT_CCtx* mtctx, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
 {
-    FORWARD_IF_ERROR( ZSTDMT_compressStream_generic(mtctx, output, input, ZSTD_e_continue) );
+    FORWARD_IF_ERROR( ZSTDMT_compressStream_generic(mtctx, output, input, ZSTD_e_continue) , "");
 
     /* recommended next input size : fill current input buffer */
     return mtctx->targetSectionSize - mtctx->inBuff.filled;   /* note : could be zero when input buffer is fully filled and no more availability to create new job */
@@ -2102,7 +2102,7 @@ static size_t ZSTDMT_flushStream_internal(ZSTDMT_CCtx* mtctx, ZSTD_outBuffer* ou
       || ((endFrame==ZSTD_e_end) && !mtctx->frameEnded)) {  /* need a last 0-size block to end frame */
            DEBUGLOG(5, "ZSTDMT_flushStream_internal : create a new job (%u bytes, end:%u)",
                         (U32)srcSize, (U32)endFrame);
-        FORWARD_IF_ERROR( ZSTDMT_createCompressionJob(mtctx, srcSize, endFrame) );
+        FORWARD_IF_ERROR( ZSTDMT_createCompressionJob(mtctx, srcSize, endFrame) , "");
     }
 
     /* check if there is any data available to flush */
diff --git a/lib/decompress/zstd_ddict.c b/lib/decompress/zstd_ddict.c
index e931597d..70477ca7 100644
--- a/lib/decompress/zstd_ddict.c
+++ b/lib/decompress/zstd_ddict.c
@@ -107,7 +107,7 @@ ZSTD_loadEntropy_intoDDict(ZSTD_DDict* ddict,
     /* load entropy tables */
     RETURN_ERROR_IF(ZSTD_isError(ZSTD_loadDEntropy(
             &ddict->entropy, ddict->dictContent, ddict->dictSize)),
-        dictionary_corrupted);
+        dictionary_corrupted, "");
     ddict->entropyPresent = 1;
     return 0;
 }
@@ -133,7 +133,7 @@ static size_t ZSTD_initDDict_internal(ZSTD_DDict* ddict,
     ddict->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001);  /* cover both little and big endian */
 
     /* parse dictionary content */
-    FORWARD_IF_ERROR( ZSTD_loadEntropy_intoDDict(ddict, dictContentType) );
+    FORWARD_IF_ERROR( ZSTD_loadEntropy_intoDDict(ddict, dictContentType) , "");
 
     return 0;
 }
diff --git a/lib/decompress/zstd_decompress.c b/lib/decompress/zstd_decompress.c
index 8353099b..91adb8a6 100644
--- a/lib/decompress/zstd_decompress.c
+++ b/lib/decompress/zstd_decompress.c
@@ -210,7 +210,7 @@ unsigned ZSTD_isFrame(const void* buffer, size_t size)
 static size_t ZSTD_frameHeaderSize_internal(const void* src, size_t srcSize, ZSTD_format_e format)
 {
     size_t const minInputSize = ZSTD_startingInputLength(format);
-    RETURN_ERROR_IF(srcSize < minInputSize, srcSize_wrong);
+    RETURN_ERROR_IF(srcSize < minInputSize, srcSize_wrong, "");
 
     {   BYTE const fhd = ((const BYTE*)src)[minInputSize-1];
         U32 const dictID= fhd & 3;
@@ -258,7 +258,7 @@ size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr, const void* src, s
             zfhPtr->frameType = ZSTD_skippableFrame;
             return 0;
         }
-        RETURN_ERROR(prefix_unknown);
+        RETURN_ERROR(prefix_unknown, "");
     }
 
     /* ensure there is enough `srcSize` to fully read/decode frame header */
@@ -282,7 +282,7 @@ size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr, const void* src, s
         if (!singleSegment) {
             BYTE const wlByte = ip[pos++];
             U32 const windowLog = (wlByte >> 3) + ZSTD_WINDOWLOG_ABSOLUTEMIN;
-            RETURN_ERROR_IF(windowLog > ZSTD_WINDOWLOG_MAX, frameParameter_windowTooLarge);
+            RETURN_ERROR_IF(windowLog > ZSTD_WINDOWLOG_MAX, frameParameter_windowTooLarge, "");
             windowSize = (1ULL << windowLog);
             windowSize += (windowSize >> 3) * (wlByte&7);
         }
@@ -354,14 +354,14 @@ static size_t readSkippableFrameSize(void const* src, size_t srcSize)
     size_t const skippableHeaderSize = ZSTD_SKIPPABLEHEADERSIZE;
     U32 sizeU32;
 
-    RETURN_ERROR_IF(srcSize < ZSTD_SKIPPABLEHEADERSIZE, srcSize_wrong);
+    RETURN_ERROR_IF(srcSize < ZSTD_SKIPPABLEHEADERSIZE, srcSize_wrong, "");
 
     sizeU32 = MEM_readLE32((BYTE const*)src + ZSTD_FRAMEIDSIZE);
     RETURN_ERROR_IF((U32)(sizeU32 + ZSTD_SKIPPABLEHEADERSIZE) < sizeU32,
-                    frameParameter_unsupported);
+                    frameParameter_unsupported, "");
     {
         size_t const skippableSize = skippableHeaderSize + sizeU32;
-        RETURN_ERROR_IF(skippableSize > srcSize, srcSize_wrong);
+        RETURN_ERROR_IF(skippableSize > srcSize, srcSize_wrong, "");
         return skippableSize;
     }
 }
@@ -441,7 +441,7 @@ static size_t ZSTD_decodeFrameHeader(ZSTD_DCtx* dctx, const void* src, size_t he
      * harder.
      */
     RETURN_ERROR_IF(dctx->fParams.dictID && (dctx->dictID != dctx->fParams.dictID),
-                    dictionary_wrong);
+                    dictionary_wrong, "");
 #endif
     if (dctx->fParams.checksumFlag) XXH64_reset(&dctx->xxhState, 0);
     return 0;
@@ -578,9 +578,9 @@ static size_t ZSTD_copyRawBlock(void* dst, size_t dstCapacity,
     DEBUGLOG(5, "ZSTD_copyRawBlock");
     if (dst == NULL) {
         if (srcSize == 0) return 0;
-        RETURN_ERROR(dstBuffer_null);
+        RETURN_ERROR(dstBuffer_null, "");
     }
-    RETURN_ERROR_IF(srcSize > dstCapacity, dstSize_tooSmall);
+    RETURN_ERROR_IF(srcSize > dstCapacity, dstSize_tooSmall, "");
     memcpy(dst, src, srcSize);
     return srcSize;
 }
@@ -591,9 +591,9 @@ static size_t ZSTD_setRleBlock(void* dst, size_t dstCapacity,
 {
     if (dst == NULL) {
         if (regenSize == 0) return 0;
-        RETURN_ERROR(dstBuffer_null);
+        RETURN_ERROR(dstBuffer_null, "");
     }
-    RETURN_ERROR_IF(regenSize > dstCapacity, dstSize_tooSmall);
+    RETURN_ERROR_IF(regenSize > dstCapacity, dstSize_tooSmall, "");
     memset(dst, b, regenSize);
     return regenSize;
 }
@@ -618,15 +618,15 @@ static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
     /* check */
     RETURN_ERROR_IF(
         remainingSrcSize < ZSTD_FRAMEHEADERSIZE_MIN(dctx->format)+ZSTD_blockHeaderSize,
-        srcSize_wrong);
+        srcSize_wrong, "");
 
     /* Frame Header */
     {   size_t const frameHeaderSize = ZSTD_frameHeaderSize_internal(
                 ip, ZSTD_FRAMEHEADERSIZE_PREFIX(dctx->format), dctx->format);
         if (ZSTD_isError(frameHeaderSize)) return frameHeaderSize;
         RETURN_ERROR_IF(remainingSrcSize < frameHeaderSize+ZSTD_blockHeaderSize,
-                        srcSize_wrong);
-        FORWARD_IF_ERROR( ZSTD_decodeFrameHeader(dctx, ip, frameHeaderSize) );
+                        srcSize_wrong, "");
+        FORWARD_IF_ERROR( ZSTD_decodeFrameHeader(dctx, ip, frameHeaderSize) , "");
         ip += frameHeaderSize; remainingSrcSize -= frameHeaderSize;
     }
 
@@ -639,7 +639,7 @@ static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
 
         ip += ZSTD_blockHeaderSize;
         remainingSrcSize -= ZSTD_blockHeaderSize;
-        RETURN_ERROR_IF(cBlockSize > remainingSrcSize, srcSize_wrong);
+        RETURN_ERROR_IF(cBlockSize > remainingSrcSize, srcSize_wrong, "");
 
         switch(blockProperties.blockType)
         {
@@ -654,7 +654,7 @@ static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
             break;
         case bt_reserved :
         default:
-            RETURN_ERROR(corruption_detected);
+            RETURN_ERROR(corruption_detected, "invalid block type");
         }
 
         if (ZSTD_isError(decodedSize)) return decodedSize;
@@ -670,14 +670,14 @@ static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
 
     if (dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN) {
         RETURN_ERROR_IF((U64)(op-ostart) != dctx->fParams.frameContentSize,
-                        corruption_detected);
+                        corruption_detected, "");
     }
     if (dctx->fParams.checksumFlag) { /* Frame content checksum verification */
         U32 const checkCalc = (U32)XXH64_digest(&dctx->xxhState);
         U32 checkRead;
-        RETURN_ERROR_IF(remainingSrcSize<4, checksum_wrong);
+        RETURN_ERROR_IF(remainingSrcSize<4, checksum_wrong, "");
         checkRead = MEM_readLE32(ip);
-        RETURN_ERROR_IF(checkRead != checkCalc, checksum_wrong);
+        RETURN_ERROR_IF(checkRead != checkCalc, checksum_wrong, "");
         ip += 4;
         remainingSrcSize -= 4;
     }
@@ -734,7 +734,7 @@ static size_t ZSTD_decompressMultiFrame(ZSTD_DCtx* dctx,
                         (unsigned)magicNumber, ZSTD_MAGICNUMBER);
             if ((magicNumber & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) {
                 size_t const skippableSize = readSkippableFrameSize(src, srcSize);
-                FORWARD_IF_ERROR(skippableSize);
+                FORWARD_IF_ERROR(skippableSize, "readSkippableFrameSize failed");
                 assert(skippableSize <= srcSize);
 
                 src = (const BYTE *)src + skippableSize;
@@ -744,11 +744,11 @@ static size_t ZSTD_decompressMultiFrame(ZSTD_DCtx* dctx,
 
         if (ddict) {
             /* we were called from ZSTD_decompress_usingDDict */
-            FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(dctx, ddict));
+            FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(dctx, ddict), "");
         } else {
             /* this will initialize correctly with no dict if dict == NULL, so
              * use this in all cases but ddict */
-            FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDict(dctx, dict, dictSize));
+            FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDict(dctx, dict, dictSize), "");
         }
         ZSTD_checkContinuity(dctx, dst);
 
@@ -818,7 +818,7 @@ size_t ZSTD_decompress(void* dst, size_t dstCapacity, const void* src, size_t sr
 #if defined(ZSTD_HEAPMODE) && (ZSTD_HEAPMODE>=1)
     size_t regenSize;
     ZSTD_DCtx* const dctx = ZSTD_createDCtx();
-    RETURN_ERROR_IF(dctx==NULL, memory_allocation);
+    RETURN_ERROR_IF(dctx==NULL, memory_allocation, "NULL pointer!");
     regenSize = ZSTD_decompressDCtx(dctx, dst, dstCapacity, src, srcSize);
     ZSTD_freeDCtx(dctx);
     return regenSize;
@@ -911,7 +911,7 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, c
     case ZSTDds_decodeFrameHeader:
         assert(src != NULL);
         memcpy(dctx->headerBuffer + (dctx->headerSize - srcSize), src, srcSize);
-        FORWARD_IF_ERROR(ZSTD_decodeFrameHeader(dctx, dctx->headerBuffer, dctx->headerSize));
+        FORWARD_IF_ERROR(ZSTD_decodeFrameHeader(dctx, dctx->headerBuffer, dctx->headerSize), "");
         dctx->expected = ZSTD_blockHeaderSize;
         dctx->stage = ZSTDds_decodeBlockHeader;
         return 0;
@@ -958,7 +958,7 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, c
             case bt_raw :
                 assert(srcSize <= dctx->expected);
                 rSize = ZSTD_copyRawBlock(dst, dstCapacity, src, srcSize);
-                FORWARD_IF_ERROR(rSize);
+                FORWARD_IF_ERROR(rSize, "ZSTD_copyRawBlock failed");
                 assert(rSize == srcSize);
                 dctx->expected -= rSize;
                 break;
@@ -968,9 +968,9 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, c
                 break;
             case bt_reserved :   /* should never happen */
             default:
-                RETURN_ERROR(corruption_detected);
+                RETURN_ERROR(corruption_detected, "invalid block type");
             }
-            FORWARD_IF_ERROR(rSize);
+            FORWARD_IF_ERROR(rSize, "");
             RETURN_ERROR_IF(rSize > dctx->fParams.blockSizeMax, corruption_detected, "Decompressed Block Size Exceeds Maximum");
             DEBUGLOG(5, "ZSTD_decompressContinue: decoded size from block : %u", (unsigned)rSize);
             dctx->decodedSize += rSize;
@@ -987,7 +987,7 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, c
                 RETURN_ERROR_IF(
                     dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN
                  && dctx->decodedSize != dctx->fParams.frameContentSize,
-                    corruption_detected);
+                    corruption_detected, "");
                 if (dctx->fParams.checksumFlag) {  /* another round for frame checksum */
                     dctx->expected = 4;
                     dctx->stage = ZSTDds_checkChecksum;
@@ -1007,7 +1007,7 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, c
         {   U32 const h32 = (U32)XXH64_digest(&dctx->xxhState);
             U32 const check32 = MEM_readLE32(src);
             DEBUGLOG(4, "ZSTD_decompressContinue: checksum : calculated %08X :: %08X read", (unsigned)h32, (unsigned)check32);
-            RETURN_ERROR_IF(check32 != h32, checksum_wrong);
+            RETURN_ERROR_IF(check32 != h32, checksum_wrong, "");
             dctx->expected = 0;
             dctx->stage = ZSTDds_getFrameHeaderSize;
             return 0;
@@ -1028,7 +1028,7 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, c
 
     default:
         assert(0);   /* impossible */
-        RETURN_ERROR(GENERIC);   /* some compiler require default to do something */
+        RETURN_ERROR(GENERIC, "impossible to reach");   /* some compiler require default to do something */
     }
 }
 
@@ -1052,7 +1052,7 @@ ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
     const BYTE* dictPtr = (const BYTE*)dict;
     const BYTE* const dictEnd = dictPtr + dictSize;
 
-    RETURN_ERROR_IF(dictSize <= 8, dictionary_corrupted);
+    RETURN_ERROR_IF(dictSize <= 8, dictionary_corrupted, "dict is too small");
     assert(MEM_readLE32(dict) == ZSTD_MAGIC_DICTIONARY);   /* dict must be valid */
     dictPtr += 8;   /* skip header = magic + dictID */
 
@@ -1071,16 +1071,16 @@ ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
                                                 dictPtr, dictEnd - dictPtr,
                                                 workspace, workspaceSize);
 #endif
-        RETURN_ERROR_IF(HUF_isError(hSize), dictionary_corrupted);
+        RETURN_ERROR_IF(HUF_isError(hSize), dictionary_corrupted, "");
         dictPtr += hSize;
     }
 
     {   short offcodeNCount[MaxOff+1];
         unsigned offcodeMaxValue = MaxOff, offcodeLog;
         size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, &offcodeMaxValue, &offcodeLog, dictPtr, dictEnd-dictPtr);
-        RETURN_ERROR_IF(FSE_isError(offcodeHeaderSize), dictionary_corrupted);
-        RETURN_ERROR_IF(offcodeMaxValue > MaxOff, dictionary_corrupted);
-        RETURN_ERROR_IF(offcodeLog > OffFSELog, dictionary_corrupted);
+        RETURN_ERROR_IF(FSE_isError(offcodeHeaderSize), dictionary_corrupted, "");
+        RETURN_ERROR_IF(offcodeMaxValue > MaxOff, dictionary_corrupted, "");
+        RETURN_ERROR_IF(offcodeLog > OffFSELog, dictionary_corrupted, "");
         ZSTD_buildFSETable( entropy->OFTable,
                             offcodeNCount, offcodeMaxValue,
                             OF_base, OF_bits,
@@ -1091,9 +1091,9 @@ ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
     {   short matchlengthNCount[MaxML+1];
         unsigned matchlengthMaxValue = MaxML, matchlengthLog;
         size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, dictEnd-dictPtr);
-        RETURN_ERROR_IF(FSE_isError(matchlengthHeaderSize), dictionary_corrupted);
-        RETURN_ERROR_IF(matchlengthMaxValue > MaxML, dictionary_corrupted);
-        RETURN_ERROR_IF(matchlengthLog > MLFSELog, dictionary_corrupted);
+        RETURN_ERROR_IF(FSE_isError(matchlengthHeaderSize), dictionary_corrupted, "");
+        RETURN_ERROR_IF(matchlengthMaxValue > MaxML, dictionary_corrupted, "");
+        RETURN_ERROR_IF(matchlengthLog > MLFSELog, dictionary_corrupted, "");
         ZSTD_buildFSETable( entropy->MLTable,
                             matchlengthNCount, matchlengthMaxValue,
                             ML_base, ML_bits,
@@ -1104,9 +1104,9 @@ ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
     {   short litlengthNCount[MaxLL+1];
         unsigned litlengthMaxValue = MaxLL, litlengthLog;
         size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, dictEnd-dictPtr);
-        RETURN_ERROR_IF(FSE_isError(litlengthHeaderSize), dictionary_corrupted);
-        RETURN_ERROR_IF(litlengthMaxValue > MaxLL, dictionary_corrupted);
-        RETURN_ERROR_IF(litlengthLog > LLFSELog, dictionary_corrupted);
+        RETURN_ERROR_IF(FSE_isError(litlengthHeaderSize), dictionary_corrupted, "");
+        RETURN_ERROR_IF(litlengthMaxValue > MaxLL, dictionary_corrupted, "");
+        RETURN_ERROR_IF(litlengthLog > LLFSELog, dictionary_corrupted, "");
         ZSTD_buildFSETable( entropy->LLTable,
                             litlengthNCount, litlengthMaxValue,
                             LL_base, LL_bits,
@@ -1114,13 +1114,13 @@ ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
         dictPtr += litlengthHeaderSize;
     }
 
-    RETURN_ERROR_IF(dictPtr+12 > dictEnd, dictionary_corrupted);
+    RETURN_ERROR_IF(dictPtr+12 > dictEnd, dictionary_corrupted, "");
     {   int i;
         size_t const dictContentSize = (size_t)(dictEnd - (dictPtr+12));
         for (i=0; i<3; i++) {
             U32 const rep = MEM_readLE32(dictPtr); dictPtr += 4;
             RETURN_ERROR_IF(rep==0 || rep > dictContentSize,
-                            dictionary_corrupted);
+                            dictionary_corrupted, "");
             entropy->rep[i] = rep;
     }   }
 
@@ -1138,7 +1138,7 @@ static size_t ZSTD_decompress_insertDictionary(ZSTD_DCtx* dctx, const void* dict
 
     /* load entropy tables */
     {   size_t const eSize = ZSTD_loadDEntropy(&dctx->entropy, dict, dictSize);
-        RETURN_ERROR_IF(ZSTD_isError(eSize), dictionary_corrupted);
+        RETURN_ERROR_IF(ZSTD_isError(eSize), dictionary_corrupted, "");
         dict = (const char*)dict + eSize;
         dictSize -= eSize;
     }
@@ -1173,11 +1173,11 @@ size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx)
 
 size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
 {
-    FORWARD_IF_ERROR( ZSTD_decompressBegin(dctx) );
+    FORWARD_IF_ERROR( ZSTD_decompressBegin(dctx) , "");
     if (dict && dictSize)
         RETURN_ERROR_IF(
             ZSTD_isError(ZSTD_decompress_insertDictionary(dctx, dict, dictSize)),
-            dictionary_corrupted);
+            dictionary_corrupted, "");
     return 0;
 }
 
@@ -1196,7 +1196,7 @@ size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
         DEBUGLOG(4, "DDict is %s",
                     dctx->ddictIsCold ? "~cold~" : "hot!");
     }
-    FORWARD_IF_ERROR( ZSTD_decompressBegin(dctx) );
+    FORWARD_IF_ERROR( ZSTD_decompressBegin(dctx) , "");
     if (ddict) {   /* NULL ddict is equivalent to no dictionary */
         ZSTD_copyDDictParameters(dctx, ddict);
     }
@@ -1287,11 +1287,11 @@ size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx,
                                          ZSTD_dictLoadMethod_e dictLoadMethod,
                                          ZSTD_dictContentType_e dictContentType)
 {
-    RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong);
+    RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, "");
     ZSTD_clearDict(dctx);
     if (dict && dictSize != 0) {
         dctx->ddictLocal = ZSTD_createDDict_advanced(dict, dictSize, dictLoadMethod, dictContentType, dctx->customMem);
-        RETURN_ERROR_IF(dctx->ddictLocal == NULL, memory_allocation);
+        RETURN_ERROR_IF(dctx->ddictLocal == NULL, memory_allocation, "NULL pointer!");
         dctx->ddict = dctx->ddictLocal;
         dctx->dictUses = ZSTD_use_indefinitely;
     }
@@ -1310,7 +1310,7 @@ size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSi
 
 size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType)
 {
-    FORWARD_IF_ERROR(ZSTD_DCtx_loadDictionary_advanced(dctx, prefix, prefixSize, ZSTD_dlm_byRef, dictContentType));
+    FORWARD_IF_ERROR(ZSTD_DCtx_loadDictionary_advanced(dctx, prefix, prefixSize, ZSTD_dlm_byRef, dictContentType), "");
     dctx->dictUses = ZSTD_use_once;
     return 0;
 }
@@ -1327,8 +1327,8 @@ size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSiz
 size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize)
 {
     DEBUGLOG(4, "ZSTD_initDStream_usingDict");
-    FORWARD_IF_ERROR( ZSTD_DCtx_reset(zds, ZSTD_reset_session_only) );
-    FORWARD_IF_ERROR( ZSTD_DCtx_loadDictionary(zds, dict, dictSize) );
+    FORWARD_IF_ERROR( ZSTD_DCtx_reset(zds, ZSTD_reset_session_only) , "");
+    FORWARD_IF_ERROR( ZSTD_DCtx_loadDictionary(zds, dict, dictSize) , "");
     return ZSTD_startingInputLength(zds->format);
 }
 
@@ -1344,8 +1344,8 @@ size_t ZSTD_initDStream(ZSTD_DStream* zds)
  * this function cannot fail */
 size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* dctx, const ZSTD_DDict* ddict)
 {
-    FORWARD_IF_ERROR( ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only) );
-    FORWARD_IF_ERROR( ZSTD_DCtx_refDDict(dctx, ddict) );
+    FORWARD_IF_ERROR( ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only) , "");
+    FORWARD_IF_ERROR( ZSTD_DCtx_refDDict(dctx, ddict) , "");
     return ZSTD_startingInputLength(dctx->format);
 }
 
@@ -1354,14 +1354,14 @@ size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* dctx, const ZSTD_DDict* ddict)
  * this function cannot fail */
 size_t ZSTD_resetDStream(ZSTD_DStream* dctx)
 {
-    FORWARD_IF_ERROR(ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only));
+    FORWARD_IF_ERROR(ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only), "");
     return ZSTD_startingInputLength(dctx->format);
 }
 
 
 size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
 {
-    RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong);
+    RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, "");
     ZSTD_clearDict(dctx);
     if (ddict) {
         dctx->ddict = ddict;
@@ -1378,9 +1378,9 @@ size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize)
     ZSTD_bounds const bounds = ZSTD_dParam_getBounds(ZSTD_d_windowLogMax);
     size_t const min = (size_t)1 << bounds.lowerBound;
     size_t const max = (size_t)1 << bounds.upperBound;
-    RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong);
-    RETURN_ERROR_IF(maxWindowSize < min, parameter_outOfBound);
-    RETURN_ERROR_IF(maxWindowSize > max, parameter_outOfBound);
+    RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, "");
+    RETURN_ERROR_IF(maxWindowSize < min, parameter_outOfBound, "");
+    RETURN_ERROR_IF(maxWindowSize > max, parameter_outOfBound, "");
     dctx->maxWindowSize = maxWindowSize;
     return 0;
 }
@@ -1426,12 +1426,12 @@ static int ZSTD_dParam_withinBounds(ZSTD_dParameter dParam, int value)
 }
 
 #define CHECK_DBOUNDS(p,v) {                \
-    RETURN_ERROR_IF(!ZSTD_dParam_withinBounds(p, v), parameter_outOfBound); \
+    RETURN_ERROR_IF(!ZSTD_dParam_withinBounds(p, v), parameter_outOfBound, ""); \
 }
 
 size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter dParam, int value)
 {
-    RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong);
+    RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, "");
     switch(dParam) {
         case ZSTD_d_windowLogMax:
             if (value == 0) value = ZSTD_WINDOWLOG_LIMIT_DEFAULT;
@@ -1448,7 +1448,7 @@ size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter dParam, int value
             return 0;
         default:;
     }
-    RETURN_ERROR(parameter_unsupported);
+    RETURN_ERROR(parameter_unsupported, "");
 }
 
 size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset)
@@ -1460,7 +1460,7 @@ size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset)
     }
     if ( (reset == ZSTD_reset_parameters)
       || (reset == ZSTD_reset_session_and_parameters) ) {
-        RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong);
+        RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, "");
         ZSTD_clearDict(dctx);
         dctx->format = ZSTD_f_zstd1;
         dctx->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT;
@@ -1481,7 +1481,7 @@ size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long
     unsigned long long const neededSize = MIN(frameContentSize, neededRBSize);
     size_t const minRBSize = (size_t) neededSize;
     RETURN_ERROR_IF((unsigned long long)minRBSize != neededSize,
-                    frameParameter_windowTooLarge);
+                    frameParameter_windowTooLarge, "");
     return minRBSize;
 }
 
@@ -1499,9 +1499,9 @@ size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize)
     ZSTD_frameHeader zfh;
     size_t const err = ZSTD_getFrameHeader(&zfh, src, srcSize);
     if (ZSTD_isError(err)) return err;
-    RETURN_ERROR_IF(err>0, srcSize_wrong);
+    RETURN_ERROR_IF(err>0, srcSize_wrong, "");
     RETURN_ERROR_IF(zfh.windowSize > windowSizeMax,
-                    frameParameter_windowTooLarge);
+                    frameParameter_windowTooLarge, "");
     return ZSTD_estimateDStreamSize((size_t)zfh.windowSize);
 }
 
@@ -1557,7 +1557,7 @@ static size_t ZSTD_decompressContinueStream(
         size_t const dstSize = isSkipFrame ? 0 : zds->outBuffSize - zds->outStart;
         size_t const decodedSize = ZSTD_decompressContinue(zds,
                 zds->outBuff + zds->outStart, dstSize, src, srcSize);
-        FORWARD_IF_ERROR(decodedSize);
+        FORWARD_IF_ERROR(decodedSize, "");
         if (!decodedSize && !isSkipFrame) {
             zds->streamStage = zdss_read;
         } else {
@@ -1568,7 +1568,7 @@ static size_t ZSTD_decompressContinueStream(
         /* Write directly into the output buffer */
         size_t const dstSize = isSkipFrame ? 0 : oend - *op;
         size_t const decodedSize = ZSTD_decompressContinue(zds, *op, dstSize, src, srcSize);
-        FORWARD_IF_ERROR(decodedSize);
+        FORWARD_IF_ERROR(decodedSize, "");
         *op += decodedSize;
         /* Flushing is not needed. */
         zds->streamStage = zdss_read;
@@ -1602,7 +1602,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
         "forbidden. out: pos: %u   vs size: %u",
         (U32)output->pos, (U32)output->size);
     DEBUGLOG(5, "input size : %u", (U32)(input->size - input->pos));
-    FORWARD_IF_ERROR(ZSTD_checkOutBuffer(zds, output));
+    FORWARD_IF_ERROR(ZSTD_checkOutBuffer(zds, output), "");
 
     while (someMoreWork) {
         switch(zds->streamStage)
@@ -1641,7 +1641,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
                             "legacy support is incompatible with static dctx");
                         FORWARD_IF_ERROR(ZSTD_initLegacyStream(&zds->legacyContext,
                                     zds->previousLegacyVersion, legacyVersion,
-                                    dict, dictSize));
+                                    dict, dictSize), "");
                         zds->legacyVersion = zds->previousLegacyVersion = legacyVersion;
                         {   size_t const hint = ZSTD_decompressLegacyStream(zds->legacyContext, legacyVersion, output, input);
                             if (hint==0) zds->streamStage = zdss_init;   /* or stay in stage zdss_loadHeader */
@@ -1695,13 +1695,13 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
 
             /* Consume header (see ZSTDds_decodeFrameHeader) */
             DEBUGLOG(4, "Consume header");
-            FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(zds, ZSTD_getDDict(zds)));
+            FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(zds, ZSTD_getDDict(zds)), "");
 
             if ((MEM_readLE32(zds->headerBuffer) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) {  /* skippable frame */
                 zds->expected = MEM_readLE32(zds->headerBuffer + ZSTD_FRAMEIDSIZE);
                 zds->stage = ZSTDds_skipFrame;
             } else {
-                FORWARD_IF_ERROR(ZSTD_decodeFrameHeader(zds, zds->headerBuffer, zds->lhSize));
+                FORWARD_IF_ERROR(ZSTD_decodeFrameHeader(zds, zds->headerBuffer, zds->lhSize), "");
                 zds->expected = ZSTD_blockHeaderSize;
                 zds->stage = ZSTDds_decodeBlockHeader;
             }
@@ -1712,7 +1712,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
                         (U32)(zds->maxWindowSize >> 10) );
             zds->fParams.windowSize = MAX(zds->fParams.windowSize, 1U << ZSTD_WINDOWLOG_ABSOLUTEMIN);
             RETURN_ERROR_IF(zds->fParams.windowSize > zds->maxWindowSize,
-                            frameParameter_windowTooLarge);
+                            frameParameter_windowTooLarge, "");
 
             /* Adapt buffer sizes to frame header instructions */
             {   size_t const neededInBuffSize = MAX(zds->fParams.blockSizeMax, 4 /* frame checksum */);
@@ -1736,13 +1736,13 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
                             assert(zds->staticSize >= sizeof(ZSTD_DCtx));  /* controlled at init */
                             RETURN_ERROR_IF(
                                 bufferSize > zds->staticSize - sizeof(ZSTD_DCtx),
-                                memory_allocation);
+                                memory_allocation, "");
                         } else {
                             ZSTD_free(zds->inBuff, zds->customMem);
                             zds->inBuffSize = 0;
                             zds->outBuffSize = 0;
                             zds->inBuff = (char*)ZSTD_malloc(bufferSize, zds->customMem);
-                            RETURN_ERROR_IF(zds->inBuff == NULL, memory_allocation);
+                            RETURN_ERROR_IF(zds->inBuff == NULL, memory_allocation, "");
                         }
                         zds->inBuffSize = neededInBuffSize;
                         zds->outBuff = zds->inBuff + zds->inBuffSize;
@@ -1761,7 +1761,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
                     break;
                 }
                 if ((size_t)(iend-ip) >= neededInSize) {  /* decode directly from src */
-                    FORWARD_IF_ERROR(ZSTD_decompressContinueStream(zds, &op, oend, ip, neededInSize));
+                    FORWARD_IF_ERROR(ZSTD_decompressContinueStream(zds, &op, oend, ip, neededInSize), "");
                     ip += neededInSize;
                     /* Function modifies the stage so we must break */
                     break;
@@ -1791,7 +1791,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
 
                 /* decode loaded input */
                 zds->inPos = 0;   /* input is consumed */
-                FORWARD_IF_ERROR(ZSTD_decompressContinueStream(zds, &op, oend, zds->inBuff, neededInSize));
+                FORWARD_IF_ERROR(ZSTD_decompressContinueStream(zds, &op, oend, zds->inBuff, neededInSize), "");
                 /* Function modifies the stage so we must break */
                 break;
             }
@@ -1817,7 +1817,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
 
         default:
             assert(0);    /* impossible */
-            RETURN_ERROR(GENERIC);   /* some compiler require default to do something */
+            RETURN_ERROR(GENERIC, "impossible to reach");   /* some compiler require default to do something */
     }   }
 
     /* result */
@@ -1830,8 +1830,8 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
     if ((ip==istart) && (op==ostart)) {  /* no forward progress */
         zds->noForwardProgress ++;
         if (zds->noForwardProgress >= ZSTD_NO_FORWARD_PROGRESS_MAX) {
-            RETURN_ERROR_IF(op==oend, dstSize_tooSmall);
-            RETURN_ERROR_IF(ip==iend, srcSize_wrong);
+            RETURN_ERROR_IF(op==oend, dstSize_tooSmall, "");
+            RETURN_ERROR_IF(ip==iend, srcSize_wrong, "");
             assert(0);
         }
     } else {
diff --git a/lib/decompress/zstd_decompress_block.c b/lib/decompress/zstd_decompress_block.c
index 521daa3d..5a1226eb 100644
--- a/lib/decompress/zstd_decompress_block.c
+++ b/lib/decompress/zstd_decompress_block.c
@@ -56,7 +56,7 @@ static void ZSTD_copy4(void* dst, const void* src) { memcpy(dst, src, 4); }
 size_t ZSTD_getcBlockSize(const void* src, size_t srcSize,
                           blockProperties_t* bpPtr)
 {
-    RETURN_ERROR_IF(srcSize < ZSTD_blockHeaderSize, srcSize_wrong);
+    RETURN_ERROR_IF(srcSize < ZSTD_blockHeaderSize, srcSize_wrong, "");
 
     {   U32 const cBlockHeader = MEM_readLE24(src);
         U32 const cSize = cBlockHeader >> 3;
@@ -64,7 +64,7 @@ size_t ZSTD_getcBlockSize(const void* src, size_t srcSize,
         bpPtr->blockType = (blockType_e)((cBlockHeader >> 1) & 3);
         bpPtr->origSize = cSize;   /* only useful for RLE */
         if (bpPtr->blockType == bt_rle) return 1;
-        RETURN_ERROR_IF(bpPtr->blockType == bt_reserved, corruption_detected);
+        RETURN_ERROR_IF(bpPtr->blockType == bt_reserved, corruption_detected, "");
         return cSize;
     }
 }
@@ -80,7 +80,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
                           const void* src, size_t srcSize)   /* note : srcSize < BLOCKSIZE */
 {
     DEBUGLOG(5, "ZSTD_decodeLiteralsBlock");
-    RETURN_ERROR_IF(srcSize < MIN_CBLOCK_SIZE, corruption_detected);
+    RETURN_ERROR_IF(srcSize < MIN_CBLOCK_SIZE, corruption_detected, "");
 
     {   const BYTE* const istart = (const BYTE*) src;
         symbolEncodingType_e const litEncType = (symbolEncodingType_e)(istart[0] & 3);
@@ -89,7 +89,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
         {
         case set_repeat:
             DEBUGLOG(5, "set_repeat flag : re-using stats from previous compressed literals block");
-            RETURN_ERROR_IF(dctx->litEntropy==0, dictionary_corrupted);
+            RETURN_ERROR_IF(dctx->litEntropy==0, dictionary_corrupted, "");
             /* fall-through */
 
         case set_compressed:
@@ -121,8 +121,8 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
                     litCSize = (lhc >> 22) + ((size_t)istart[4] << 10);
                     break;
                 }
-                RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected);
-                RETURN_ERROR_IF(litCSize + lhSize > srcSize, corruption_detected);
+                RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected, "");
+                RETURN_ERROR_IF(litCSize + lhSize > srcSize, corruption_detected, "");
 
                 /* prefetch huffman table if cold */
                 if (dctx->ddictIsCold && (litSize > 768 /* heuristic */)) {
@@ -160,7 +160,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
                     }
                 }
 
-                RETURN_ERROR_IF(HUF_isError(hufSuccess), corruption_detected);
+                RETURN_ERROR_IF(HUF_isError(hufSuccess), corruption_detected, "");
 
                 dctx->litPtr = dctx->litBuffer;
                 dctx->litSize = litSize;
@@ -190,7 +190,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
                 }
 
                 if (lhSize+litSize+WILDCOPY_OVERLENGTH > srcSize) {  /* risk reading beyond src buffer with wildcopy */
-                    RETURN_ERROR_IF(litSize+lhSize > srcSize, corruption_detected);
+                    RETURN_ERROR_IF(litSize+lhSize > srcSize, corruption_detected, "");
                     memcpy(dctx->litBuffer, istart+lhSize, litSize);
                     dctx->litPtr = dctx->litBuffer;
                     dctx->litSize = litSize;
@@ -222,7 +222,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
                     RETURN_ERROR_IF(srcSize<4, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 3; here we need lhSize+1 = 4");
                     break;
                 }
-                RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected);
+                RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected, "");
                 memset(dctx->litBuffer, istart[lhSize], litSize + WILDCOPY_OVERLENGTH);
                 dctx->litPtr = dctx->litBuffer;
                 dctx->litSize = litSize;
@@ -440,8 +440,8 @@ static size_t ZSTD_buildSeqTable(ZSTD_seqSymbol* DTableSpace, const ZSTD_seqSymb
     switch(type)
     {
     case set_rle :
-        RETURN_ERROR_IF(!srcSize, srcSize_wrong);
-        RETURN_ERROR_IF((*(const BYTE*)src) > max, corruption_detected);
+        RETURN_ERROR_IF(!srcSize, srcSize_wrong, "");
+        RETURN_ERROR_IF((*(const BYTE*)src) > max, corruption_detected, "");
         {   U32 const symbol = *(const BYTE*)src;
             U32 const baseline = baseValue[symbol];
             U32 const nbBits = nbAdditionalBits[symbol];
@@ -453,7 +453,7 @@ static size_t ZSTD_buildSeqTable(ZSTD_seqSymbol* DTableSpace, const ZSTD_seqSymb
         *DTablePtr = defaultTable;
         return 0;
     case set_repeat:
-        RETURN_ERROR_IF(!flagRepeatTable, corruption_detected);
+        RETURN_ERROR_IF(!flagRepeatTable, corruption_detected, "");
         /* prefetch FSE table if used */
         if (ddictIsCold && (nbSeq > 24 /* heuristic */)) {
             const void* const pStart = *DTablePtr;
@@ -465,8 +465,8 @@ static size_t ZSTD_buildSeqTable(ZSTD_seqSymbol* DTableSpace, const ZSTD_seqSymb
         {   unsigned tableLog;
             S16 norm[MaxSeq+1];
             size_t const headerSize = FSE_readNCount(norm, &max, &tableLog, src, srcSize);
-            RETURN_ERROR_IF(FSE_isError(headerSize), corruption_detected);
-            RETURN_ERROR_IF(tableLog > maxLog, corruption_detected);
+            RETURN_ERROR_IF(FSE_isError(headerSize), corruption_detected, "");
+            RETURN_ERROR_IF(tableLog > maxLog, corruption_detected, "");
             ZSTD_buildFSETable(DTableSpace, norm, max, baseValue, nbAdditionalBits, tableLog);
             *DTablePtr = DTableSpace;
             return headerSize;
@@ -487,28 +487,28 @@ size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr,
     DEBUGLOG(5, "ZSTD_decodeSeqHeaders");
 
     /* check */
-    RETURN_ERROR_IF(srcSize < MIN_SEQUENCES_SIZE, srcSize_wrong);
+    RETURN_ERROR_IF(srcSize < MIN_SEQUENCES_SIZE, srcSize_wrong, "");
 
     /* SeqHead */
     nbSeq = *ip++;
     if (!nbSeq) {
         *nbSeqPtr=0;
-        RETURN_ERROR_IF(srcSize != 1, srcSize_wrong);
+        RETURN_ERROR_IF(srcSize != 1, srcSize_wrong, "");
         return 1;
     }
     if (nbSeq > 0x7F) {
         if (nbSeq == 0xFF) {
-            RETURN_ERROR_IF(ip+2 > iend, srcSize_wrong);
+            RETURN_ERROR_IF(ip+2 > iend, srcSize_wrong, "");
             nbSeq = MEM_readLE16(ip) + LONGNBSEQ, ip+=2;
         } else {
-            RETURN_ERROR_IF(ip >= iend, srcSize_wrong);
+            RETURN_ERROR_IF(ip >= iend, srcSize_wrong, "");
             nbSeq = ((nbSeq-0x80)<<8) + *ip++;
         }
     }
     *nbSeqPtr = nbSeq;
 
     /* FSE table descriptors */
-    RETURN_ERROR_IF(ip+1 > iend, srcSize_wrong); /* minimum possible size: 1 byte for symbol encoding types */
+    RETURN_ERROR_IF(ip+1 > iend, srcSize_wrong, ""); /* minimum possible size: 1 byte for symbol encoding types */
     {   symbolEncodingType_e const LLtype = (symbolEncodingType_e)(*ip >> 6);
         symbolEncodingType_e const OFtype = (symbolEncodingType_e)((*ip >> 4) & 3);
         symbolEncodingType_e const MLtype = (symbolEncodingType_e)((*ip >> 2) & 3);
@@ -521,7 +521,7 @@ size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr,
                                                       LL_base, LL_bits,
                                                       LL_defaultDTable, dctx->fseEntropy,
                                                       dctx->ddictIsCold, nbSeq);
-            RETURN_ERROR_IF(ZSTD_isError(llhSize), corruption_detected);
+            RETURN_ERROR_IF(ZSTD_isError(llhSize), corruption_detected, "ZSTD_buildSeqTable failed");
             ip += llhSize;
         }
 
@@ -531,7 +531,7 @@ size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr,
                                                       OF_base, OF_bits,
                                                       OF_defaultDTable, dctx->fseEntropy,
                                                       dctx->ddictIsCold, nbSeq);
-            RETURN_ERROR_IF(ZSTD_isError(ofhSize), corruption_detected);
+            RETURN_ERROR_IF(ZSTD_isError(ofhSize), corruption_detected, "ZSTD_buildSeqTable failed");
             ip += ofhSize;
         }
 
@@ -541,7 +541,7 @@ size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr,
                                                       ML_base, ML_bits,
                                                       ML_defaultDTable, dctx->fseEntropy,
                                                       dctx->ddictIsCold, nbSeq);
-            RETURN_ERROR_IF(ZSTD_isError(mlhSize), corruption_detected);
+            RETURN_ERROR_IF(ZSTD_isError(mlhSize), corruption_detected, "ZSTD_buildSeqTable failed");
             ip += mlhSize;
         }
     }
@@ -683,7 +683,7 @@ size_t ZSTD_execSequenceEnd(BYTE* op,
     /* copy Match */
     if (sequence.offset > (size_t)(oLitEnd - prefixStart)) {
         /* offset beyond prefix */
-        RETURN_ERROR_IF(sequence.offset > (size_t)(oLitEnd - virtualStart), corruption_detected);
+        RETURN_ERROR_IF(sequence.offset > (size_t)(oLitEnd - virtualStart), corruption_detected, "");
         match = dictEnd - (prefixStart-match);
         if (match + sequence.matchLength <= dictEnd) {
             memmove(oLitEnd, match, sequence.matchLength);
@@ -738,7 +738,7 @@ size_t ZSTD_execSequence(BYTE* op,
     /* Copy Match */
     if (sequence.offset > (size_t)(oLitEnd - prefixStart)) {
         /* offset beyond prefix -> go into extDict */
-        RETURN_ERROR_IF(UNLIKELY(sequence.offset > (size_t)(oLitEnd - virtualStart)), corruption_detected);
+        RETURN_ERROR_IF(UNLIKELY(sequence.offset > (size_t)(oLitEnd - virtualStart)), corruption_detected, "");
         match = dictEnd + (match - prefixStart);
         if (match + sequence.matchLength <= dictEnd) {
             memmove(oLitEnd, match, sequence.matchLength);
@@ -964,7 +964,7 @@ ZSTD_decompressSequences_body( ZSTD_DCtx* dctx,
         { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; }
         RETURN_ERROR_IF(
             ERR_isError(BIT_initDStream(&seqState.DStream, ip, iend-ip)),
-            corruption_detected);
+            corruption_detected, "");
         ZSTD_initFseState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
         ZSTD_initFseState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
         ZSTD_initFseState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
@@ -1034,15 +1034,15 @@ ZSTD_decompressSequences_body( ZSTD_DCtx* dctx,
         /* check if reached exact end */
         DEBUGLOG(5, "ZSTD_decompressSequences_body: after decode loop, remaining nbSeq : %i", nbSeq);
         if (ZSTD_isError(error)) return error;
-        RETURN_ERROR_IF(nbSeq, corruption_detected);
-        RETURN_ERROR_IF(BIT_reloadDStream(&seqState.DStream) < BIT_DStream_completed, corruption_detected);
+        RETURN_ERROR_IF(nbSeq, corruption_detected, "");
+        RETURN_ERROR_IF(BIT_reloadDStream(&seqState.DStream) < BIT_DStream_completed, corruption_detected, "");
         /* save reps for next block */
         { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]); }
     }
 
     /* last literal segment */
     {   size_t const lastLLSize = litEnd - litPtr;
-        RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall);
+        RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, "");
         memcpy(op, litPtr, lastLLSize);
         op += lastLLSize;
     }
@@ -1096,7 +1096,7 @@ ZSTD_decompressSequencesLong_body(
         assert(iend >= ip);
         RETURN_ERROR_IF(
             ERR_isError(BIT_initDStream(&seqState.DStream, ip, iend-ip)),
-            corruption_detected);
+            corruption_detected, "");
         ZSTD_initFseState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
         ZSTD_initFseState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
         ZSTD_initFseState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
@@ -1106,7 +1106,7 @@ ZSTD_decompressSequencesLong_body(
             sequences[seqNb] = ZSTD_decodeSequence(&seqState, isLongOffset, ZSTD_p_prefetch);
             PREFETCH_L1(sequences[seqNb].match); PREFETCH_L1(sequences[seqNb].match + sequences[seqNb].matchLength - 1); /* note : it's safe to invoke PREFETCH() on any memory address, including invalid ones */
         }
-        RETURN_ERROR_IF(seqNb<seqAdvance, corruption_detected);
+        RETURN_ERROR_IF(seqNb<seqAdvance, corruption_detected, "");
 
         /* decode and decompress */
         for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && (seqNb<nbSeq) ; seqNb++) {
@@ -1117,7 +1117,7 @@ ZSTD_decompressSequencesLong_body(
             sequences[seqNb & STORED_SEQS_MASK] = sequence;
             op += oneSeqSize;
         }
-        RETURN_ERROR_IF(seqNb<nbSeq, corruption_detected);
+        RETURN_ERROR_IF(seqNb<nbSeq, corruption_detected, "");
 
         /* finish queue */
         seqNb -= seqAdvance;
@@ -1133,7 +1133,7 @@ ZSTD_decompressSequencesLong_body(
 
     /* last literal segment */
     {   size_t const lastLLSize = litEnd - litPtr;
-        RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall);
+        RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, "");
         memcpy(op, litPtr, lastLLSize);
         op += lastLLSize;
     }
@@ -1271,7 +1271,7 @@ ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx,
     ZSTD_longOffset_e const isLongOffset = (ZSTD_longOffset_e)(MEM_32bits() && (!frame || (dctx->fParams.windowSize > (1ULL << STREAM_ACCUMULATOR_MIN))));
     DEBUGLOG(5, "ZSTD_decompressBlock_internal (size : %u)", (U32)srcSize);
 
-    RETURN_ERROR_IF(srcSize >= ZSTD_BLOCKSIZE_MAX, srcSize_wrong);
+    RETURN_ERROR_IF(srcSize >= ZSTD_BLOCKSIZE_MAX, srcSize_wrong, "");
 
     /* Decode literals section */
     {   size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize);
diff --git a/lib/legacy/zstd_v01.c b/lib/legacy/zstd_v01.c
index f8eb21db..4d5ecf7d 100644
--- a/lib/legacy/zstd_v01.c
+++ b/lib/legacy/zstd_v01.c
@@ -257,7 +257,7 @@ static U64 FSE_read64(const void* memPtr)
     U64 val; memcpy(&val, memPtr, sizeof(val)); return val;
 }
 
-#endif // FSE_FORCE_MEMORY_ACCESS
+#endif /* FSE_FORCE_MEMORY_ACCESS */
 
 static U16 FSE_readLE16(const void* memPtr)
 {
@@ -1092,7 +1092,7 @@ static size_t HUF_decompress_usingDTable(   /* -3% slower when non static */
         const size_t length1 = FSE_readLE16(jumpTable);
         const size_t length2 = FSE_readLE16(jumpTable+1);
         const size_t length3 = FSE_readLE16(jumpTable+2);
-        const size_t length4 = cSrcSize - 6 - length1 - length2 - length3;   // check coherency !!
+        const size_t length4 = cSrcSize - 6 - length1 - length2 - length3;   /* check coherency !! */
         const char* const start1 = (const char*)(cSrc) + 6;
         const char* const start2 = start1 + length1;
         const char* const start3 = start2 + length2;
@@ -1150,11 +1150,11 @@ static size_t HUF_decompress_usingDTable(   /* -3% slower when non static */
 
         /* tail */
         {
-            // bitTail = bitD1;   // *much* slower : -20% !??!
+            /* bitTail = bitD1; */   /* *much* slower : -20% !??! */
             FSE_DStream_t bitTail;
             bitTail.ptr = bitD1.ptr;
             bitTail.bitsConsumed = bitD1.bitsConsumed;
-            bitTail.bitContainer = bitD1.bitContainer;   // required in case of FSE_DStream_endOfBuffer
+            bitTail.bitContainer = bitD1.bitContainer;   /* required in case of FSE_DStream_endOfBuffer */
             bitTail.start = start1;
             for ( ; (FSE_reloadDStream(&bitTail) < FSE_DStream_completed) && (op<omax) ; op++)
             {
@@ -1502,7 +1502,7 @@ static size_t ZSTD_decompressLiterals(void* ctx,
     if (srcSize <= 3) return ERROR(corruption_detected);
 
     litSize = ip[1] + (ip[0]<<8);
-    litSize += ((ip[-3] >> 3) & 7) << 16;   // mmmmh....
+    litSize += ((ip[-3] >> 3) & 7) << 16;   /* mmmmh.... */
     op = oend - litSize;
 
     (void)ctx;
diff --git a/lib/legacy/zstd_v02.c b/lib/legacy/zstd_v02.c
index dc4a3e8a..7105aa49 100644
--- a/lib/legacy/zstd_v02.c
+++ b/lib/legacy/zstd_v02.c
@@ -189,7 +189,7 @@ MEM_STATIC void MEM_write16(void* memPtr, U16 value)
     memcpy(memPtr, &value, sizeof(value));
 }
 
-#endif // MEM_FORCE_MEMORY_ACCESS
+#endif /* MEM_FORCE_MEMORY_ACCESS */
 
 
 MEM_STATIC U16 MEM_readLE16(const void* memPtr)
diff --git a/lib/legacy/zstd_v03.c b/lib/legacy/zstd_v03.c
index f0c26b8e..980cf02f 100644
--- a/lib/legacy/zstd_v03.c
+++ b/lib/legacy/zstd_v03.c
@@ -191,7 +191,7 @@ MEM_STATIC void MEM_write16(void* memPtr, U16 value)
 }
 
 
-#endif // MEM_FORCE_MEMORY_ACCESS
+#endif /* MEM_FORCE_MEMORY_ACCESS */
 
 
 MEM_STATIC U16 MEM_readLE16(const void* memPtr)
diff --git a/lib/legacy/zstd_v04.c b/lib/legacy/zstd_v04.c
index bf344543..e5b51f78 100644
--- a/lib/legacy/zstd_v04.c
+++ b/lib/legacy/zstd_v04.c
@@ -161,7 +161,7 @@ MEM_STATIC void MEM_write16(void* memPtr, U16 value)
     memcpy(memPtr, &value, sizeof(value));
 }
 
-#endif // MEM_FORCE_MEMORY_ACCESS
+#endif /* MEM_FORCE_MEMORY_ACCESS */
 
 
 MEM_STATIC U16 MEM_readLE16(const void* memPtr)
diff --git a/lib/legacy/zstd_v05.c b/lib/legacy/zstd_v05.c
index 07355ecb..649144d0 100644
--- a/lib/legacy/zstd_v05.c
+++ b/lib/legacy/zstd_v05.c
@@ -1804,7 +1804,7 @@ static size_t HUFv05_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
 
     if (!srcSize) return ERROR(srcSize_wrong);
     iSize = ip[0];
-    //memset(huffWeight, 0, hwSize);   /* is not necessary, even though some analyzer complain ... */
+    /* memset(huffWeight, 0, hwSize); */   /* is not necessary, even though some analyzer complain ... */
 
     if (iSize >= 128)  { /* special header */
         if (iSize >= (242)) {  /* RLE */
@@ -1879,7 +1879,7 @@ size_t HUFv05_readDTableX2 (U16* DTable, const void* src, size_t srcSize)
     HUFv05_DEltX2* const dt = (HUFv05_DEltX2*)dtPtr;
 
     HUFv05_STATIC_ASSERT(sizeof(HUFv05_DEltX2) == sizeof(U16));   /* if compilation fails here, assertion is false */
-    //memset(huffWeight, 0, sizeof(huffWeight));   /* is not necessary, even though some analyzer complain ... */
+    /* memset(huffWeight, 0, sizeof(huffWeight)); */   /* is not necessary, even though some analyzer complain ... */
 
     iSize = HUFv05_readStats(huffWeight, HUFv05_MAX_SYMBOL_VALUE + 1, rankVal, &nbSymbols, &tableLog, src, srcSize);
     if (HUFv05_isError(iSize)) return iSize;
@@ -2210,7 +2210,7 @@ size_t HUFv05_readDTableX4 (unsigned* DTable, const void* src, size_t srcSize)
 
     HUFv05_STATIC_ASSERT(sizeof(HUFv05_DEltX4) == sizeof(unsigned));   /* if compilation fails here, assertion is false */
     if (memLog > HUFv05_ABSOLUTEMAX_TABLELOG) return ERROR(tableLog_tooLarge);
-    //memset(weightList, 0, sizeof(weightList));   /* is not necessary, even though some analyzer complain ... */
+    /* memset(weightList, 0, sizeof(weightList)); */   /* is not necessary, even though some analyzer complain ... */
 
     iSize = HUFv05_readStats(weightList, HUFv05_MAX_SYMBOL_VALUE + 1, rankStats, &nbSymbols, &tableLog, src, srcSize);
     if (HUFv05_isError(iSize)) return iSize;
@@ -2539,9 +2539,9 @@ size_t HUFv05_decompress (void* dst, size_t dstSize, const void* cSrc, size_t cS
 
     return decompress[algoNb](dst, dstSize, cSrc, cSrcSize);
 
-    //return HUFv05_decompress4X2(dst, dstSize, cSrc, cSrcSize);   /* multi-streams single-symbol decoding */
-    //return HUFv05_decompress4X4(dst, dstSize, cSrc, cSrcSize);   /* multi-streams double-symbols decoding */
-    //return HUFv05_decompress4X6(dst, dstSize, cSrc, cSrcSize);   /* multi-streams quad-symbols decoding */
+    /* return HUFv05_decompress4X2(dst, dstSize, cSrc, cSrcSize); */   /* multi-streams single-symbol decoding */
+    /* return HUFv05_decompress4X4(dst, dstSize, cSrc, cSrcSize); */   /* multi-streams double-symbols decoding */
+    /* return HUFv05_decompress4X6(dst, dstSize, cSrc, cSrcSize); */   /* multi-streams quad-symbols decoding */
 }
 /*
     zstd - standard compression library
@@ -3930,7 +3930,7 @@ size_t ZBUFFv05_decompressContinue(ZBUFFv05_DCtx* zbc, void* dst, size_t* maxDst
                     *maxDstSizePtr = 0;
                     return headerSize - zbc->hPos;
                 }
-                // zbc->stage = ZBUFFv05ds_decodeHeader; break;   /* useless : stage follows */
+                /* zbc->stage = ZBUFFv05ds_decodeHeader; break; */   /* useless : stage follows */
             }
 	    /* fall-through */
         case ZBUFFv05ds_decodeHeader:
@@ -4003,7 +4003,7 @@ size_t ZBUFFv05_decompressContinue(ZBUFFv05_DCtx* zbc, void* dst, size_t* maxDst
                     if (!decodedSize) { zbc->stage = ZBUFFv05ds_read; break; }   /* this was just a header */
                     zbc->outEnd = zbc->outStart +  decodedSize;
                     zbc->stage = ZBUFFv05ds_flush;
-                    // break; /* ZBUFFv05ds_flush follows */
+                    /* break; */  /* ZBUFFv05ds_flush follows */
                 }
 	    }
 	    /* fall-through */
diff --git a/lib/legacy/zstd_v06.c b/lib/legacy/zstd_v06.c
index b957e5b0..288eebe8 100644
--- a/lib/legacy/zstd_v06.c
+++ b/lib/legacy/zstd_v06.c
@@ -1862,7 +1862,7 @@ MEM_STATIC size_t HUFv06_readStats(BYTE* huffWeight, size_t hwSize, U32* rankSta
 
     if (!srcSize) return ERROR(srcSize_wrong);
     iSize = ip[0];
-    //memset(huffWeight, 0, hwSize);   /* is not necessary, even though some analyzer complain ... */
+    /* memset(huffWeight, 0, hwSize); */   /* is not necessary, even though some analyzer complain ... */
 
     if (iSize >= 128)  { /* special header */
         if (iSize >= (242)) {  /* RLE */
@@ -2014,7 +2014,7 @@ size_t HUFv06_readDTableX2 (U16* DTable, const void* src, size_t srcSize)
     HUFv06_DEltX2* const dt = (HUFv06_DEltX2*)dtPtr;
 
     HUFv06_STATIC_ASSERT(sizeof(HUFv06_DEltX2) == sizeof(U16));   /* if compilation fails here, assertion is false */
-    //memset(huffWeight, 0, sizeof(huffWeight));   /* is not necessary, even though some analyzer complain ... */
+    /* memset(huffWeight, 0, sizeof(huffWeight)); */   /* is not necessary, even though some analyzer complain ... */
 
     iSize = HUFv06_readStats(huffWeight, HUFv06_MAX_SYMBOL_VALUE + 1, rankVal, &nbSymbols, &tableLog, src, srcSize);
     if (HUFv06_isError(iSize)) return iSize;
@@ -2340,7 +2340,7 @@ size_t HUFv06_readDTableX4 (U32* DTable, const void* src, size_t srcSize)
 
     HUFv06_STATIC_ASSERT(sizeof(HUFv06_DEltX4) == sizeof(U32));   /* if compilation fails here, assertion is false */
     if (memLog > HUFv06_ABSOLUTEMAX_TABLELOG) return ERROR(tableLog_tooLarge);
-    //memset(weightList, 0, sizeof(weightList));   /* is not necessary, even though some analyzer complain ... */
+    /* memset(weightList, 0, sizeof(weightList)); */   /* is not necessary, even though some analyzer complain ... */
 
     iSize = HUFv06_readStats(weightList, HUFv06_MAX_SYMBOL_VALUE + 1, rankStats, &nbSymbols, &tableLog, src, srcSize);
     if (HUFv06_isError(iSize)) return iSize;
@@ -2664,13 +2664,13 @@ size_t HUFv06_decompress (void* dst, size_t dstSize, const void* cSrc, size_t cS
 
     {   U32 algoNb = 0;
         if (Dtime[1] < Dtime[0]) algoNb = 1;
-        // if (Dtime[2] < Dtime[algoNb]) algoNb = 2;   /* current speed of HUFv06_decompress4X6 is not good */
+        /* if (Dtime[2] < Dtime[algoNb]) algoNb = 2; */   /* current speed of HUFv06_decompress4X6 is not good */
         return decompress[algoNb](dst, dstSize, cSrc, cSrcSize);
     }
 
-    //return HUFv06_decompress4X2(dst, dstSize, cSrc, cSrcSize);   /* multi-streams single-symbol decoding */
-    //return HUFv06_decompress4X4(dst, dstSize, cSrc, cSrcSize);   /* multi-streams double-symbols decoding */
-    //return HUFv06_decompress4X6(dst, dstSize, cSrc, cSrcSize);   /* multi-streams quad-symbols decoding */
+    /* return HUFv06_decompress4X2(dst, dstSize, cSrc, cSrcSize); */   /* multi-streams single-symbol decoding */
+    /* return HUFv06_decompress4X4(dst, dstSize, cSrc, cSrcSize); */   /* multi-streams double-symbols decoding */
+    /* return HUFv06_decompress4X6(dst, dstSize, cSrc, cSrcSize); */   /* multi-streams quad-symbols decoding */
 }
 /*
     Common functions of Zstd compression library
@@ -4111,7 +4111,7 @@ size_t ZBUFFv06_decompressContinue(ZBUFFv06_DCtx* zbd,
                     if (!decodedSize) { zbd->stage = ZBUFFds_read; break; }   /* this was just a header */
                     zbd->outEnd = zbd->outStart +  decodedSize;
                     zbd->stage = ZBUFFds_flush;
-                    // break; /* ZBUFFds_flush follows */
+                    /* break; */ /* ZBUFFds_flush follows */
                 }
 	    }
 	    /* fall-through */
diff --git a/lib/legacy/zstd_v07.c b/lib/legacy/zstd_v07.c
index 1a93bb93..36593d38 100644
--- a/lib/legacy/zstd_v07.c
+++ b/lib/legacy/zstd_v07.c
@@ -1314,7 +1314,7 @@ size_t HUFv07_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
 
     if (!srcSize) return ERROR(srcSize_wrong);
     iSize = ip[0];
-    //memset(huffWeight, 0, hwSize);   /* is not necessary, even though some analyzer complain ... */
+    /* memset(huffWeight, 0, hwSize); */   /* is not necessary, even though some analyzer complain ... */
 
     if (iSize >= 128)  { /* special header */
         if (iSize >= (242)) {  /* RLE */
@@ -1784,7 +1784,7 @@ size_t HUFv07_readDTableX2 (HUFv07_DTable* DTable, const void* src, size_t srcSi
     HUFv07_DEltX2* const dt = (HUFv07_DEltX2*)dtPtr;
 
     HUFv07_STATIC_ASSERT(sizeof(DTableDesc) == sizeof(HUFv07_DTable));
-    //memset(huffWeight, 0, sizeof(huffWeight));   /* is not necessary, even though some analyzer complain ... */
+    /* memset(huffWeight, 0, sizeof(huffWeight)); */   /* is not necessary, even though some analyzer complain ... */
 
     iSize = HUFv07_readStats(huffWeight, HUFv07_SYMBOLVALUE_MAX + 1, rankVal, &nbSymbols, &tableLog, src, srcSize);
     if (HUFv07_isError(iSize)) return iSize;
@@ -2148,7 +2148,7 @@ size_t HUFv07_readDTableX4 (HUFv07_DTable* DTable, const void* src, size_t srcSi
 
     HUFv07_STATIC_ASSERT(sizeof(HUFv07_DEltX4) == sizeof(HUFv07_DTable));   /* if compilation fails here, assertion is false */
     if (maxTableLog > HUFv07_TABLELOG_ABSOLUTEMAX) return ERROR(tableLog_tooLarge);
-    //memset(weightList, 0, sizeof(weightList));   /* is not necessary, even though some analyzer complain ... */
+    /* memset(weightList, 0, sizeof(weightList)); */   /* is not necessary, even though some analyzer complain ... */
 
     iSize = HUFv07_readStats(weightList, HUFv07_SYMBOLVALUE_MAX + 1, rankStats, &nbSymbols, &tableLog, src, srcSize);
     if (HUFv07_isError(iSize)) return iSize;
@@ -2530,8 +2530,8 @@ size_t HUFv07_decompress (void* dst, size_t dstSize, const void* cSrc, size_t cS
         return decompress[algoNb](dst, dstSize, cSrc, cSrcSize);
     }
 
-    //return HUFv07_decompress4X2(dst, dstSize, cSrc, cSrcSize);   /* multi-streams single-symbol decoding */
-    //return HUFv07_decompress4X4(dst, dstSize, cSrc, cSrcSize);   /* multi-streams double-symbols decoding */
+    /* return HUFv07_decompress4X2(dst, dstSize, cSrc, cSrcSize); */   /* multi-streams single-symbol decoding */
+    /* return HUFv07_decompress4X4(dst, dstSize, cSrc, cSrcSize); */   /* multi-streams double-symbols decoding */
 }
 
 size_t HUFv07_decompress4X_DCtx (HUFv07_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize)
@@ -3712,7 +3712,7 @@ static size_t ZSTDv07_decompressSequences(
 
     /* last literal segment */
     {   size_t const lastLLSize = litEnd - litPtr;
-        //if (litPtr > litEnd) return ERROR(corruption_detected);   /* too many literals already used */
+        /* if (litPtr > litEnd) return ERROR(corruption_detected); */   /* too many literals already used */
         if (lastLLSize > (size_t)(oend-op)) return ERROR(dstSize_tooSmall);
         memcpy(op, litPtr, lastLLSize);
         op += lastLLSize;
diff --git a/tests/fuzzer.c b/tests/fuzzer.c
index 700cb577..23346810 100644
--- a/tests/fuzzer.c
+++ b/tests/fuzzer.c
@@ -28,6 +28,7 @@
 #undef NDEBUG
 #include <assert.h>
 #define ZSTD_STATIC_LINKING_ONLY  /* ZSTD_compressContinue, ZSTD_compressBlock */
+#include "debug.h"        /* DEBUG_STATIC_ASSERT */
 #include "fse.h"
 #include "zstd.h"         /* ZSTD_VERSION_STRING */
 #include "zstd_errors.h"  /* ZSTD_getErrorCode */
@@ -456,10 +457,42 @@ static int basicUnitTests(U32 const seed, double compressibility)
 
     DISPLAYLEVEL(3, "test%3i : misc unaccounted for zstd symbols : ", testNb++);
     {
-        DISPLAYLEVEL(3, "%p ", ZSTD_getDictID_fromDDict);
-        DISPLAYLEVEL(3, "%p ", ZSTD_createDStream_advanced);
-        DISPLAYLEVEL(3, "%p ", ZSTD_copyDCtx);
-        DISPLAYLEVEL(3, "%p ", ZSTD_nextInputType);
+        /* %p takes a void*. In ISO C, it's illegal to cast a function pointer
+         * to a data pointer. (Although in POSIX you're required to be allowed
+         * to do it...) So we have to fall back to our trusty friend memcpy. */
+        unsigned (* const funcptr_getDictID)(const ZSTD_DDict* ddict) =
+            ZSTD_getDictID_fromDDict;
+        ZSTD_DStream* (* const funcptr_createDStream)(
+            ZSTD_customMem customMem) = ZSTD_createDStream_advanced;
+        void (* const funcptr_copyDCtx)(
+            ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx) = ZSTD_copyDCtx;
+        ZSTD_nextInputType_e (* const funcptr_nextInputType)(ZSTD_DCtx* dctx) =
+            ZSTD_nextInputType;
+        const void *voidptr_getDictID;
+        const void *voidptr_createDStream;
+        const void *voidptr_copyDCtx;
+        const void *voidptr_nextInputType;
+        DEBUG_STATIC_ASSERT(sizeof(funcptr_getDictID) == sizeof(voidptr_getDictID));
+        memcpy(
+            (void*)&voidptr_getDictID,
+            (const void*)&funcptr_getDictID,
+            sizeof(void*));
+        memcpy(
+            (void*)&voidptr_createDStream,
+            (const void*)&funcptr_createDStream,
+            sizeof(void*));
+        memcpy(
+            (void*)&voidptr_copyDCtx,
+            (const void*)&funcptr_copyDCtx,
+            sizeof(void*));
+        memcpy(
+            (void*)&voidptr_nextInputType,
+            (const void*)&funcptr_nextInputType,
+            sizeof(void*));
+        DISPLAYLEVEL(3, "%p ", voidptr_getDictID);
+        DISPLAYLEVEL(3, "%p ", voidptr_createDStream);
+        DISPLAYLEVEL(3, "%p ", voidptr_copyDCtx);
+        DISPLAYLEVEL(3, "%p ", voidptr_nextInputType);
     }
     DISPLAYLEVEL(3, ": OK \n");
 
diff --git a/tests/zstreamtest.c b/tests/zstreamtest.c
index 3fc96eb1..79d5a828 100644
--- a/tests/zstreamtest.c
+++ b/tests/zstreamtest.c
@@ -1452,12 +1452,12 @@ static int basicUnitTests(U32 seed, double compressibility)
 
         /* and includes a very long backref */
         cursegmentlen = 128;
-        memcpy(inbuf + inbufpos, dictionary.start + 256, cursegmentlen);
+        memcpy(inbuf + inbufpos, (BYTE*)dictionary.start + 256, cursegmentlen);
         inbufpos += cursegmentlen;
 
         /* and includes a very long backref */
         cursegmentlen = 128;
-        memcpy(inbuf + inbufpos, dictionary.start + 128, cursegmentlen);
+        memcpy(inbuf + inbufpos, (BYTE*)dictionary.start + 128, cursegmentlen);
         inbufpos += cursegmentlen;
 
         ret = ZSTD_compress_usingCDict(zc, outbuf, outbufsize, inbuf, inbufpos, cdict);
@@ -1500,7 +1500,7 @@ static int basicUnitTests(U32 seed, double compressibility)
         }
         /* Write several very long offset matches into the dictionary */
         for (offset = 1024; offset >= 0; offset -= 128) {
-          ZSTD_inBuffer in = {dictionary.start + offset, 128, 0};
+          ZSTD_inBuffer in = {(BYTE*)dictionary.start + offset, 128, 0};
           ZSTD_EndDirective flush = offset > 0 ? ZSTD_e_continue : ZSTD_e_end;
           CHECK_Z(ZSTD_compressStream2(zc, &out, &in, flush));
           CHECK(in.pos != in.size, "input not fully consumed");