diff --git a/Makefile b/Makefile
index 7dc64953..59af7a01 100644
--- a/Makefile
+++ b/Makefile
@@ -64,7 +64,7 @@ zlibwrapper:
 
 .PHONY: test
 test:
-	$(MAKE) -C $(PRGDIR) allVariants MOREFLAGS+="-g -DZSTD_DEBUG=1"
+	$(MAKE) -C $(PRGDIR) allVariants MOREFLAGS+="-g -DDEBUGLEVEL=1"
 	$(MAKE) -C $(TESTDIR) $@
 
 .PHONY: shortest
diff --git a/lib/common/bitstream.h b/lib/common/bitstream.h
index 04440fde..2f91460c 100644
--- a/lib/common/bitstream.h
+++ b/lib/common/bitstream.h
@@ -1,8 +1,7 @@
 /* ******************************************************************
    bitstream
    Part of FSE library
-   header file (to include)
-   Copyright (C) 2013-2017, Yann Collet.
+   Copyright (C) 2013-present, Yann Collet.
 
    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
@@ -49,45 +48,10 @@ extern "C" {
 *  Dependencies
 ******************************************/
 #include "mem.h"            /* unaligned access routines */
+#include "debug.h"          /* assert(), DEBUGLOG(), RAWLOG() */
 #include "error_private.h"  /* error codes and messages */
 
 
-/*-*************************************
-*  Debug
-***************************************/
-#if defined(BIT_DEBUG) && (BIT_DEBUG>=1)
-#  include <assert.h>
-#else
-#  ifndef assert
-#    define assert(condition) ((void)0)
-#  endif
-#endif
-
-#if defined(BIT_DEBUG) && (BIT_DEBUG>=2)
-#  include <stdio.h>
-extern int g_debuglog_enable;
-/* recommended values for BIT_DEBUG display levels :
- * 1 : no display, enables assert() only
- * 2 : reserved for currently active debug path
- * 3 : events once per object lifetime (CCtx, CDict, etc.)
- * 4 : events once per frame
- * 5 : events once per block
- * 6 : events once per sequence (*very* verbose) */
-#  define RAWLOG(l, ...) {                                      \
-                if ((g_debuglog_enable) & (l<=BIT_DEBUG)) {    \
-                    fprintf(stderr, __VA_ARGS__);               \
-            }   }
-#  define DEBUGLOG(l, ...) {                                    \
-                if ((g_debuglog_enable) & (l<=BIT_DEBUG)) {    \
-                    fprintf(stderr, __FILE__ ": " __VA_ARGS__); \
-                    fprintf(stderr, " \n");                     \
-            }   }
-#else
-#  define RAWLOG(l, ...)      {}    /* disabled */
-#  define DEBUGLOG(l, ...)    {}    /* disabled */
-#endif
-
-
 /*=========================================
 *  Target specific
 =========================================*/
@@ -107,8 +71,7 @@ extern int g_debuglog_enable;
  * A critical property of these streams is that they encode and decode in **reverse** direction.
  * So the first bit sequence you add will be the last to be read, like a LIFO stack.
  */
-typedef struct
-{
+typedef struct {
     size_t bitContainer;
     unsigned bitPos;
     char*  startPtr;
@@ -142,8 +105,7 @@ MEM_STATIC size_t BIT_closeCStream(BIT_CStream_t* bitC);
 /*-********************************************
 *  bitStream decoding API (read backward)
 **********************************************/
-typedef struct
-{
+typedef struct {
     size_t   bitContainer;
     unsigned bitsConsumed;
     const char* ptr;
@@ -260,7 +222,8 @@ MEM_STATIC void BIT_addBits(BIT_CStream_t* bitC,
 }
 
 /*! BIT_addBitsFast() :
- *  works only if `value` is _clean_, meaning all high bits above nbBits are 0 */
+ *  works only if `value` is _clean_,
+ *  meaning all high bits above nbBits are 0 */
 MEM_STATIC void BIT_addBitsFast(BIT_CStream_t* bitC,
                                 size_t value, unsigned nbBits)
 {
diff --git a/lib/common/debug.c b/lib/common/debug.c
new file mode 100644
index 00000000..3ebdd1cb
--- /dev/null
+++ b/lib/common/debug.c
@@ -0,0 +1,44 @@
+/* ******************************************************************
+   debug
+   Part of FSE library
+   Copyright (C) 2013-present, Yann Collet.
+
+   BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are
+   met:
+
+       * Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above
+   copyright notice, this list of conditions and the following disclaimer
+   in the documentation and/or other materials provided with the
+   distribution.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+   You can contact the author at :
+   - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
+****************************************************************** */
+
+
+/*
+ * This module only hosts one global variable
+ * which can be used to dynamically influence the verbosity of traces,
+ * such as DEBUGLOG and RAWLOG
+ */
+
+#include "debug.h"
+
+int g_debuglevel = DEBUGLEVEL;
diff --git a/lib/common/debug.h b/lib/common/debug.h
new file mode 100644
index 00000000..95a3fcab
--- /dev/null
+++ b/lib/common/debug.h
@@ -0,0 +1,121 @@
+/* ******************************************************************
+   debug
+   Part of FSE library
+   Copyright (C) 2013-present, Yann Collet.
+
+   BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are
+   met:
+
+       * Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above
+   copyright notice, this list of conditions and the following disclaimer
+   in the documentation and/or other materials provided with the
+   distribution.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+   You can contact the author at :
+   - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
+****************************************************************** */
+
+
+/*
+ * The purpose of this header is to enable debug functions.
+ * They regroup assert(), DEBUGLOG() and RAWLOG().
+ *
+ * By default, DEBUGLEVEL==0, which means debug is disabled.
+ *
+ * Level 1 enables assert() only.
+ * Starting level 2, traces can be generated and pushed to stderr.
+ * The higher the level, the more verbose the traces.
+ *
+ * It's possible to dynamically adjust level using variable g_debug_level,
+ * which is only declared if DEBUGLEVEL>=2,
+ * and is a global variable, not multi-thread protected (use with care)
+ */
+
+#ifndef DEBUG_H_12987983217
+#define DEBUG_H_12987983217
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+
+/* static assert is triggered at compile time, leaving no runtime artefact,
+ * but can only work with compile-time constants */
+#define DEBUG_STATIC_ASSERT(c) { enum { DEBUG_static_assert = 1/(int)(!!(c)) }; }
+
+
+/* DEBUGLEVEL is expected to be defined externally,
+ * typically through compiler command line.
+ * Value must be a number. */
+#ifndef DEBUGLEVEL
+#  define DEBUGLEVEL 0
+#endif
+
+/* recommended values for DEBUGLEVEL :
+ * 0 : no debug, all functions disabled (except DEBUG_STATIC_ASSERT)
+ * 1 : no display, enables assert() only
+ * 2 : reserved, for currently active debug path
+ * 3 : events once per object lifetime (CCtx, CDict, etc.)
+ * 4 : events once per frame
+ * 5 : events once per block
+ * 6 : events once per sequence (verbose)
+ * 7+: events at every position (*very* verbose)
+ *
+ * It's generally inconvenient to output traces > 5.
+ * In which case, it's possible to selectively enable higher verbosity levels
+ * by modifying g_debug_level.
+ */
+
+#if (DEBUGLEVEL>=1)
+#  include <assert.h>
+#else
+#  ifndef assert   /* assert may be already defined, due to prior #include <assert.h> */
+#    define assert(condition) ((void)0)   /* disable assert (default) */
+#  endif
+#endif
+
+#if (DEBUGLEVEL>=2)
+#  include <stdio.h>
+extern int g_debuglevel; /* here, this variable is only declared,
+                           it actually lives in debug.c,
+                           and is shared by the whole process.
+                           It's typically used to enable very verbose levels
+                           on selective conditions (such as position in src) */
+
+#  define RAWLOG(l, ...) {                                      \
+                if (l<=g_debuglevel) {                          \
+                    fprintf(stderr, __VA_ARGS__);               \
+            }   }
+#  define DEBUGLOG(l, ...) {                                    \
+                if (l<=g_debuglevel) {                          \
+                    fprintf(stderr, __FILE__ ": " __VA_ARGS__); \
+                    fprintf(stderr, " \n");                     \
+            }   }
+#else
+#  define RAWLOG(l, ...)      {}    /* disabled */
+#  define DEBUGLOG(l, ...)    {}    /* disabled */
+#endif
+
+
+#if defined (__cplusplus)
+}
+#endif
+
+#endif /* DEBUG_H_12987983217 */
diff --git a/lib/common/fse_decompress.c b/lib/common/fse_decompress.c
index 4c66c3b7..72bbead5 100644
--- a/lib/common/fse_decompress.c
+++ b/lib/common/fse_decompress.c
@@ -49,7 +49,7 @@
 *  Error Management
 ****************************************************************/
 #define FSE_isError ERR_isError
-#define FSE_STATIC_ASSERT(c) { enum { FSE_static_assert = 1/(int)(!!(c)) }; }   /* use only *after* variable declarations */
+#define FSE_STATIC_ASSERT(c) DEBUG_STATIC_ASSERT(c)   /* use only *after* variable declarations */
 
 /* check and forward error code */
 #define CHECK_F(f) { size_t const e = f; if (FSE_isError(e)) return e; }
diff --git a/lib/common/zstd_common.c b/lib/common/zstd_common.c
index 64aa8575..6f05d240 100644
--- a/lib/common/zstd_common.c
+++ b/lib/common/zstd_common.c
@@ -46,11 +46,6 @@ ZSTD_ErrorCode ZSTD_getErrorCode(size_t code) { return ERR_getErrorCode(code); }
  *  provides error code string from enum */
 const char* ZSTD_getErrorString(ZSTD_ErrorCode code) { return ERR_getErrorString(code); }
 
-/*! g_debuglog_enable :
- *  turn on/off debug traces (global switch) */
-#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG >= 2)
-int g_debuglevel = ZSTD_DEBUG;
-#endif
 
 
 /*=**************************************************************
diff --git a/lib/common/zstd_internal.h b/lib/common/zstd_internal.h
index 86d96b5a..b4c1af53 100644
--- a/lib/common/zstd_internal.h
+++ b/lib/common/zstd_internal.h
@@ -21,6 +21,7 @@
 ***************************************/
 #include "compiler.h"
 #include "mem.h"
+#include "debug.h"                 /* assert, DEBUGLOG, RAWLOG, g_debuglevel */
 #include "error_private.h"
 #define ZSTD_STATIC_LINKING_ONLY
 #include "zstd.h"
@@ -38,45 +39,8 @@
 extern "C" {
 #endif
 
-
-/*-*************************************
-*  Debug
-***************************************/
-#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=1)
-#  include <assert.h>
-#else
-#  ifndef assert
-#    define assert(condition) ((void)0)
-#  endif
-#endif
-
-#define ZSTD_STATIC_ASSERT(c) { enum { ZSTD_static_assert = 1/(int)(!!(c)) }; }
-
-#undef RAWLOG
-#undef DEBUGLOG
-#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=2)
-#  include <stdio.h>
-extern int g_debuglevel;
-/* recommended values for ZSTD_DEBUG display levels :
- * 1 : no display, enables assert() only
- * 2 : reserved for currently active debug path
- * 3 : events once per object lifetime (CCtx, CDict, etc.)
- * 4 : events once per frame
- * 5 : events once per block
- * 6 : events once per sequence (*very* verbose) */
-#  define RAWLOG(l, ...) {                                      \
-                if (l<=g_debuglevel) {                          \
-                    fprintf(stderr, __VA_ARGS__);               \
-            }   }
-#  define DEBUGLOG(l, ...) {                                    \
-                if (l<=g_debuglevel) {                          \
-                    fprintf(stderr, __FILE__ ": " __VA_ARGS__); \
-                    fprintf(stderr, " \n");                     \
-            }   }
-#else
-#  define RAWLOG(l, ...)      {}    /* disabled */
-#  define DEBUGLOG(l, ...)    {}    /* disabled */
-#endif
+/* ---- static assert (debug) --- */
+#define ZSTD_STATIC_ASSERT(c) DEBUG_STATIC_ASSERT(c)
 
 
 /*-*************************************
diff --git a/lib/compress/fse_compress.c b/lib/compress/fse_compress.c
index ab2eb335..eeff3f2c 100644
--- a/lib/compress/fse_compress.c
+++ b/lib/compress/fse_compress.c
@@ -49,7 +49,7 @@
 *  Error Management
 ****************************************************************/
 #define FSE_isError ERR_isError
-#define FSE_STATIC_ASSERT(c) { enum { FSE_static_assert = 1/(int)(!!(c)) }; }   /* use only *after* variable declarations */
+#define FSE_STATIC_ASSERT(c) DEBUG_STATIC_ASSERT(c)   /* use only *after* variable declarations */
 
 
 /* **************************************************************
diff --git a/lib/compress/huf_compress.c b/lib/compress/huf_compress.c
index c01a2381..b927efcc 100644
--- a/lib/compress/huf_compress.c
+++ b/lib/compress/huf_compress.c
@@ -58,7 +58,7 @@
 *  Error Management
 ****************************************************************/
 #define HUF_isError ERR_isError
-#define HUF_STATIC_ASSERT(c) { enum { HUF_static_assert = 1/(int)(!!(c)) }; }   /* use only *after* variable declarations */
+#define HUF_STATIC_ASSERT(c) DEBUG_STATIC_ASSERT(c)   /* use only *after* variable declarations */
 #define CHECK_V_F(e, f) size_t const e = f; if (ERR_isError(e)) return e
 #define CHECK_F(f)   { CHECK_V_F(_var_err__, f); }
 
diff --git a/lib/compress/zstd_compress_internal.h b/lib/compress/zstd_compress_internal.h
index ef3e5952..ec9d01cc 100644
--- a/lib/compress/zstd_compress_internal.h
+++ b/lib/compress/zstd_compress_internal.h
@@ -298,7 +298,7 @@ MEM_STATIC U32 ZSTD_MLcode(U32 mlBase)
 */
 MEM_STATIC void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const void* literals, U32 offsetCode, size_t mlBase)
 {
-#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG >= 6)
+#if defined(DEBUGLEVEL) && (DEBUGLEVEL >= 6)
     static const BYTE* g_start = NULL;
     if (g_start==NULL) g_start = (const BYTE*)literals;  /* note : index only works for compression within a single segment */
     {   U32 const pos = (U32)((const BYTE*)literals - g_start);
diff --git a/lib/compress/zstdmt_compress.c b/lib/compress/zstdmt_compress.c
index 102da896..0c59c6a7 100644
--- a/lib/compress/zstdmt_compress.c
+++ b/lib/compress/zstdmt_compress.c
@@ -37,18 +37,17 @@
 #define ZSTD_RESIZE_SEQPOOL 0
 
 /* ======   Debug   ====== */
-#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=2)
+#if defined(DEBUGLEVEL) && (DEBUGLEVEL>=2)
 
 #  include <stdio.h>
 #  include <unistd.h>
 #  include <sys/times.h>
-#  define DEBUGLOGRAW(l, ...) if (l<=ZSTD_DEBUG) { fprintf(stderr, __VA_ARGS__); }
 
 #  define DEBUG_PRINTHEX(l,p,n) {            \
     unsigned debug_u;                        \
     for (debug_u=0; debug_u<(n); debug_u++)  \
-        DEBUGLOGRAW(l, "%02X ", ((const unsigned char*)(p))[debug_u]); \
-    DEBUGLOGRAW(l, " \n");                   \
+        RAWLOG(l, "%02X ", ((const unsigned char*)(p))[debug_u]); \
+    RAWLOG(l, " \n");                   \
 }
 
 static unsigned long long GetCurrentClockTimeMicroseconds(void)
@@ -62,7 +61,7 @@ static unsigned long long GetCurrentClockTimeMicroseconds(void)
 
 #define MUTEX_WAIT_TIME_DLEVEL 6
 #define ZSTD_PTHREAD_MUTEX_LOCK(mutex) {          \
-    if (ZSTD_DEBUG >= MUTEX_WAIT_TIME_DLEVEL) {   \
+    if (DEBUGLEVEL >= MUTEX_WAIT_TIME_DLEVEL) {   \
         unsigned long long const beforeTime = GetCurrentClockTimeMicroseconds(); \
         ZSTD_pthread_mutex_lock(mutex);           \
         {   unsigned long long const afterTime = GetCurrentClockTimeMicroseconds(); \
diff --git a/lib/decompress/huf_decompress.c b/lib/decompress/huf_decompress.c
index 2c2d1380..dc722e59 100644
--- a/lib/decompress/huf_decompress.c
+++ b/lib/decompress/huf_decompress.c
@@ -48,7 +48,7 @@
 *  Error Management
 ****************************************************************/
 #define HUF_isError ERR_isError
-#define HUF_STATIC_ASSERT(c) { enum { HUF_static_assert = 1/(int)(!!(c)) }; }   /* use only *after* variable declarations */
+#define HUF_STATIC_ASSERT(c) DEBUG_STATIC_ASSERT(c)   /* use only *after* variable declarations */
 #define CHECK_F(f) { size_t const err_ = (f); if (HUF_isError(err_)) return err_; }
 
 
diff --git a/lib/dictBuilder/zdict.c b/lib/dictBuilder/zdict.c
index 427438f0..2024e0bb 100644
--- a/lib/dictBuilder/zdict.c
+++ b/lib/dictBuilder/zdict.c
@@ -1089,8 +1089,8 @@ size_t ZDICT_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity,
     params.steps = 4;
     /* Default to level 6 since no compression level information is available */
     params.zParams.compressionLevel = 6;
-#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=1)
-    params.zParams.notificationLevel = ZSTD_DEBUG;
+#if defined(DEBUGLEVEL) && (DEBUGLEVEL>=1)
+    params.zParams.notificationLevel = DEBUGLEVEL;
 #endif
     return ZDICT_optimizeTrainFromBuffer_cover(dictBuffer, dictBufferCapacity,
                                                samplesBuffer, samplesSizes, nbSamples,
diff --git a/lib/legacy/zstd_v04.c b/lib/legacy/zstd_v04.c
index 0dd7c4f2..a2e2cfa8 100644
--- a/lib/legacy/zstd_v04.c
+++ b/lib/legacy/zstd_v04.c
@@ -74,38 +74,9 @@ extern "C" {
 /*-*************************************
 *  Debug
 ***************************************/
-#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=1)
-#  include <assert.h>
-#else
-#  ifndef assert
-#    define assert(condition) ((void)0)
-#  endif
-#endif
-
-#define ZSTD_STATIC_ASSERT(c) { enum { ZSTD_static_assert = 1/(int)(!!(c)) }; }
-
-#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=2)
-#  include <stdio.h>
-extern int g_debuglevel;
-/* recommended values for ZSTD_DEBUG display levels :
- * 1 : no display, enables assert() only
- * 2 : reserved for currently active debug path
- * 3 : events once per object lifetime (CCtx, CDict, etc.)
- * 4 : events once per frame
- * 5 : events once per block
- * 6 : events once per sequence (*very* verbose) */
-#  define RAWLOG(l, ...) {                                      \
-                if (l<=g_debuglevel) {                          \
-                    fprintf(stderr, __VA_ARGS__);               \
-            }   }
-#  define DEBUGLOG(l, ...) {                                    \
-                if (l<=g_debuglevel) {                          \
-                    fprintf(stderr, __FILE__ ": " __VA_ARGS__); \
-                    fprintf(stderr, " \n");                     \
-            }   }
-#else
-#  define RAWLOG(l, ...)      {}    /* disabled */
-#  define DEBUGLOG(l, ...)    {}    /* disabled */
+#include "debug.h"
+#ifndef assert
+#  define assert(condition) ((void)0)
 #endif
 
 
diff --git a/tests/Makefile b/tests/Makefile
index c1482bc9..3b828bdd 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -24,7 +24,7 @@ PYTHON ?= python3
 TESTARTEFACT := versionsTest
 
 DEBUGLEVEL ?= 1
-DEBUGFLAGS  = -g -DZSTD_DEBUG=$(DEBUGLEVEL) -DBIT_DEBUG=$(DEBUGLEVEL)
+DEBUGFLAGS  = -g -DDEBUGLEVEL=$(DEBUGLEVEL)
 CPPFLAGS   += -I$(ZSTDDIR) -I$(ZSTDDIR)/common -I$(ZSTDDIR)/compress \
               -I$(ZSTDDIR)/dictBuilder -I$(ZSTDDIR)/deprecated -I$(PRGDIR)
 CFLAGS     ?= -O3
diff --git a/tests/fuzz/fuzz.h b/tests/fuzz/fuzz.h
index a6484547..8850025b 100644
--- a/tests/fuzz/fuzz.h
+++ b/tests/fuzz/fuzz.h
@@ -23,10 +23,10 @@
  *        the data to zstd functions. Every fuzzer initializes the RNG exactly
  *        once before doing anything else, even if it is unused.
  *        Default: 4.
- * @param ZSTD_DEBUG:
- *        This is a parameter for the zstd library. Defining `ZSTD_DEBUG=1`
+ * @param DEBUGLEVEL:
+ *        This is a parameter for the zstd library. Defining `DEBUGLEVEL=1`
  *        enables assert() statements in the zstd library. Higher levels enable
- *        logging, so aren't recommended. Defining `ZSTD_DEBUG=1` is
+ *        logging, so aren't recommended. Defining `DEBUGLEVEL=1` is
  *        recommended.
  * @param MEM_FORCE_MEMORY_ACCESS:
  *        This flag controls how the zstd library accesses unaligned memory.
diff --git a/tests/fuzz/fuzz.py b/tests/fuzz/fuzz.py
index 04d9c600..84c28c63 100755
--- a/tests/fuzz/fuzz.py
+++ b/tests/fuzz/fuzz.py
@@ -251,7 +251,7 @@ def build_parser(args):
         dest='debug',
         type=int,
         default=1,
-        help='Set ZSTD_DEBUG and BIT_DEBUG (default: 1)')
+        help='Set DEBUGLEVEL (default: 1)')
     parser.add_argument(
         '--force-memory-access',
         dest='memory_access',
@@ -358,8 +358,7 @@ def build(args):
     common_flags = []
 
     cppflags += [
-        '-DZSTD_DEBUG={}'.format(args.debug),
-        '-DBIT_DEBUG={}'.format(args.debug),
+        '-DDEBUGLEVEL={}'.format(args.debug),
         '-DMEM_FORCE_MEMORY_ACCESS={}'.format(args.memory_access),
         '-DFUZZ_RNG_SEED_SIZE={}'.format(args.fuzz_rng_seed_size),
     ]