Changeset 30112 in vbox for trunk/include

Timestamp:

Jun 9, 2010 12:31:50 PM (15 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

62507

Message:

iprt/asm.h,*: Added ASMAtomicWriteNullPtr and ASMAtomicUoWriteNullPtr to better deal with NULL being 0 in C++.

File:

• trunk/include/iprt/asm.h (modified) (4 diffs)

trunk/include/iprt/asm.h

@@ -2416 +2416 @@
  * Atomically writes a pointer value, ordered.
  *
- * @returns Current *pv value
  * @param   ppv     Pointer to the pointer variable.
  * @param   pv      The pointer value to assign to *ppv.
@@ -2433 +2432 @@
 
 /**
- * Convenience macro for avoiding the annoying casting with ASMAtomicWritePtr.
- *
- * @returns Current *pv value
+ * Atomically writes a pointer value, ordered.
+ *
  * @param   ppv     Pointer to the pointer variable.
- * @param   pv      The pointer value to assign to *ppv. If NULL, you may have
- *                  to cast it to the right pointer type for GCC to be happy.
+ * @param   pv      The pointer value to assign to *ppv. If NULL use
+ *                  ASMAtomicWriteNullPtr or you'll land in trouble.
  *
  * @remarks This is relatively type safe on GCC platforms when @a pv isn't
@@ -2470 +2468 @@
 
 /**
- * Convenience macro for avoiding the annoying casting involved when using
- * ASMAtomicWritePtr.
+ * Atomically sets a pointer to NULL, ordered.
+ *
+ * @param   ppv     Pointer to the pointer variable that should be set to NULL.
+ *
+ * @remarks This is relatively type safe on GCC platforms.
+ */
+#ifdef __GNUC__
+# define ASMAtomicWriteNullPtr(ppv) \
+    do \
+    { \
+        __typeof__(*(ppv)) volatile * const ppvTypeChecked = (ppv); \
+        AssertCompile(sizeof(*ppv) == sizeof(void *)); \
+        Assert(!( (uintptr_t)ppv & ((ARCH_BITS / 8) - 1) )); \
+        ASMAtomicWritePtrVoid((void * volatile *)(ppvTypeChecked), NULL); \
+    } while (0)
+#else
+# define ASMAtomicWriteNullPtr(ppv) \
+    do \
+    { \
+        AssertCompile(sizeof(*ppv) == sizeof(void *)); \
+        Assert(!( (uintptr_t)ppv & ((ARCH_BITS / 8) - 1) )); \
+        ASMAtomicWritePtrVoid((void * volatile *)(ppv), NULL); \
+    } while (0)
+#endif
+
+
+/**
+ * Atomically writes a pointer value, unordered.
  *
  * @returns Current *pv value
  * @param   ppv     Pointer to the pointer variable.
- * @param   pv      The pointer value to assign to *ppv.
+ * @param   pv      The pointer value to assign to *ppv. If NULL use
+ *                  ASMAtomicUoWriteNullPtr or you'll land in trouble.
  *
  * @remarks This is relatively type safe on GCC platforms when @a pv isn't
@@ -2501 +2526 @@
         Assert(!( (uintptr_t)ppv & ((ARCH_BITS / 8) - 1) )); \
         *(ppv) = pv; \
+    } while (0)
+#endif
+
+
+/**
+ * Atomically sets a pointer to NULL, unordered.
+ *
+ * @param   ppv     Pointer to the pointer variable that should be set to NULL.
+ *
+ * @remarks This is relatively type safe on GCC platforms.
+ */
+#ifdef __GNUC__
+# define ASMAtomicUoWriteNullPtr(ppv) \
+    do \
+    { \
+        __typeof__(*(ppv)) volatile * const ppvTypeChecked = (ppv); \
+        AssertCompile(sizeof(*ppv) == sizeof(void *)); \
+        Assert(!( (uintptr_t)ppv & ((ARCH_BITS / 8) - 1) )); \
+        *(ppvTypeChecked) = NULL; \
+    } while (0)
+#else
+# define ASMAtomicUoWriteNullPtr(ppv) \
+    do \
+    { \
+        AssertCompile(sizeof(*ppv) == sizeof(void *)); \
+        Assert(!( (uintptr_t)ppv & ((ARCH_BITS / 8) - 1) )); \
+        *(ppv) = NULL; \
     } while (0)
 #endif