added comment about MSVC compiler barrier intrinsics

diff --git a/src/common/pa_memorybarrier.h b/src/common/pa_memorybarrier.h
index f6896222010f6d6d48ce32e0660e828d173da668..2879ce33adc4ba42b70019c18cd65a9618eeb48f 100644 (file)
--- a/src/common/pa_memorybarrier.h
+++ b/src/common/pa_memorybarrier.h
@@ -103,6 +103,7 @@
 #   pragma intrinsic(_ReadWriteBarrier)
 #   pragma intrinsic(_ReadBarrier)
 #   pragma intrinsic(_WriteBarrier)
+/* note that MSVC intrinsics _ReadWriteBarrier(), _ReadBarrier(), _WriteBarrier() are just compiler barriers *not* memory barriers */
 #   define PaUtil_FullMemoryBarrier()  _ReadWriteBarrier()
 #   define PaUtil_ReadMemoryBarrier()  _ReadBarrier()
 #   define PaUtil_WriteMemoryBarrier() _WriteBarrier()