mem: add memcheck() for valgrind.

[ccan] / ccan / mem / mem.h

diff --git a/ccan/mem/mem.h b/ccan/mem/mem.h
index dd66cc62cd8cce990aeac17da41962aa2bf74a74..68a4aa3c18885c207a9fd11828bc5174bead6905 100644 (file)
--- a/ccan/mem/mem.h
+++ b/ccan/mem/mem.h
@@ -227,4 +227,39 @@ static inline bool memoverlaps(const void *a_, size_t al,
  */
 void memswap(void *a, void *b, size_t n);
 
+#if HAVE_VALGRIND_MEMCHECK_H
+#include <valgrind/memcheck.h>
+static inline void *memcheck_(const void *data, size_t len)
+{
+       VALGRIND_CHECK_MEM_IS_DEFINED(data, len);
+       return (void *)data;
+}
+#else
+static inline void *memcheck_(const void *data, size_t len)
+{
+       return (void *)data;
+}
+#endif
+
+#if HAVE_TYPEOF
+/**
+ * memcheck - check that a memory region is initialized
+ * @data: start of region
+ * @len: length in bytes
+ *
+ * When running under valgrind, this causes an error to be printed
+ * if the entire region is not defined.  Otherwise valgrind only
+ * reports an error when an undefined value is used for a branch, or
+ * written out.
+ *
+ * Example:
+ *     // Search for space, but make sure it's all initialized.
+ *     if (memchr(memcheck(somebytes, bytes_len), ' ', bytes_len)) {
+ *             printf("space was found!\n");
+ *     }
+ */
+#define memcheck(data, len) ((__typeof__((data)+0))memcheck_((data), (len)))
+#else
+#define memcheck(data, len) memcheck_((data), (len))
+#endif
 #endif /* CCAN_MEM_H */