Do an atomic compare-exchange on the global context when destroying a context

2 files changed, 15 insertions, 6 deletions

diff --git a/Alc/ALc.c b/Alc/ALc.c
index df2ba12c..6ce6feaa 100644
--- a/Alc/ALc.c
+++ b/Alc/ALc.c
@@ -2147,17 +2147,14 @@ ALC_API ALCvoid ALC_APIENTRY alcDestroyContext(ALCcontext *context)
     }
     UnlockDevice(Device);
 
+    if(CompExchangePtr((void**)&GlobalContext, context, NULL))
+        ALCcontext_DecRef(context);
+
     if(Device->NumContexts == 0)
     {
         ALCdevice_StopPlayback(Device);
         Device->Flags &= ~DEVICE_RUNNING;
     }
-
-    if(GlobalContext == context)
-    {
-        GlobalContext = NULL;
-        ALCcontext_DecRef(context);
-    }
     UnlockLists();
 
     ALCcontext_DecRef(context);
diff --git a/OpenAL32/Include/alMain.h b/OpenAL32/Include/alMain.h
index ae24f54c..4e596d09 100644
--- a/OpenAL32/Include/alMain.h
+++ b/OpenAL32/Include/alMain.h
@@ -243,6 +243,10 @@ static __inline ALboolean CompExchangeInt(volatile int *ptr, int oldval, int new
 {
     return __sync_bool_compare_and_swap(ptr, oldval, newval);
 }
+static __inline ALboolean CompExchangePtr(void *volatile*ptr, void *oldval, void *newval)
+{
+    return __sync_bool_compare_and_swap(ptr, oldval, newval);
+}
 
 #elif defined(_WIN32)
 
@@ -274,6 +278,10 @@ static __inline ALboolean CompExchangeInt(volatile int *ptr, int oldval, int new
     } u = { ptr };
     return InterlockedCompareExchange(u.l, newval, oldval) == oldval;
 }
+static __inline void *CompExchangePtr(void *volatile*ptr, void *oldval, void *newval)
+{
+    return InterlockedCompareExchangePointer(ptr, newval, oldval);
+}
 
 #elif defined(__APPLE__)
 
@@ -306,6 +314,10 @@ static __inline ALboolean CompExchangeInt(volatile int *ptr, int oldval, int new
 {
     return OSAtomicCompareAndSwap32Barrier(oldval, newval, ptr);
 }
+static __inline ALboolean CompExchangeInt(void *volatile*ptr, void *oldval, void *newval)
+{
+    return OSAtomicCompareAndSwapPtrBarrier(oldval, newval, ptr);
+}
 
 #else
 #error "No atomic functions available on this platform!"