Add an option to trap context errors in a debugger

Alc/ALc.c

@@ -34,6 +34,7 @@
 #include "alSource.h"
 #include "alBuffer.h"
 #include "alAuxEffectSlot.h"
+#include "alError.h"
 #include "bs2b.h"
 #include "alu.h"
 
@@ -498,6 +499,10 @@ static void alc_init(void)
     if(str && (strcasecmp(str, "true") == 0 || strtol(str, NULL, 0) == 1))
         ZScale = -1.0;
 
+    str = getenv("__ALSOFT_TRAP_AL_ERROR");
+    if(str && (strcasecmp(str, "true") == 0 || strtol(str, NULL, 0) == 1))
+        TrapALError = AL_TRUE;
+
     pthread_key_create(&LocalContext, ReleaseThreadCtx);
     InitializeCriticalSection(&ListLock);
     ThunkInit();
@@ -569,6 +574,9 @@ static void alc_initconfig(void)
     if(DefaultResampler >= RESAMPLER_MAX || DefaultResampler <= RESAMPLER_MIN)
         DefaultResampler = RESAMPLER_DEFAULT;
 
+    if(!TrapALError)
+        TrapALError = GetConfigValueBool(NULL, "trap-al-error", AL_FALSE);
+
     ReverbBoost *= aluPow(10.0f, GetConfigValueFloat("reverb", "boost", 0.0f) /
                                  20.0f);
     EmulateEAXReverb = GetConfigValueBool("reverb", "emulate-eax", AL_FALSE);

OpenAL32/Include/alError.h

@@ -8,6 +8,8 @@
 extern "C" {
 #endif
 
+extern ALboolean TrapALError;
+
 ALvoid alSetError(ALCcontext *Context, ALenum errorCode);
 
 #ifdef __cplusplus

OpenAL32/alError.c

@@ -20,10 +20,14 @@
 
 #include "config.h"
 
+#include <signal.h>
+
 #include "alMain.h"
 #include "AL/alc.h"
 #include "alError.h"
 
+ALboolean TrapALError = AL_FALSE;
+
 AL_API ALenum AL_APIENTRY alGetError(void)
 {
     ALCcontext *Context;
@@ -41,5 +45,18 @@ AL_API ALenum AL_APIENTRY alGetError(void)
 
 ALvoid alSetError(ALCcontext *Context, ALenum errorCode)
 {
+    if(TrapALError)
+    {
+#ifdef _WIN32
+        /* Safely catch a breakpoint exception that wasn't caught by a debugger */
+        __try  {
+            DebugBreak();
+        } __except((GetExceptionCode()==EXCEPTION_BREAKPOINT) ?
+                   EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
+        }
+#elif defined(SIGTRAP)
+        kill(getpid(), SIGTRAP);
+#endif
+    }
     CompExchangeInt(&Context->LastError, AL_NO_ERROR, errorCode);
 }

alsoftrc.sample

@@ -150,6 +150,14 @@
 #layout_61CHN  = fl=-30, fr=30, fc=0, sl=-90, sr=90, bc=180
 #layout_71CHN  = fl=-30, fr=30, fc=0, sl=-90, sr=90, bl=-150, br=150
 
+## trap-al-error:
+#  Generates a SIGTRAP signal when an AL context error is generated, on systems
+#  that support it. This helps when debugging, while trying to find the cause
+#  of a context error. On Windows, a breakpoint exception is generated.
+#  Optionally, the __ALSOFT_TRAP_AL_ERROR env var may be set before running the
+#  app instead.
+#trap-al-error = false
+
 ##
 ## Reverb effect stuff (includes EAX reverb)
 ##