*/
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 */
--- /dev/null
+#include "config.h"
+
+#include <assert.h>
+
+#include <ccan/mem/mem.h>
+#include <ccan/tap/tap.h>
+
+int main(void)
+{
+ char haystack[] = "abcd\0efgh";
+ char *p;
+ const char *pc;
+
+ /* This is how many tests you plan to run */
+ plan_tests(4);
+
+ p = memcheck(haystack, sizeof(haystack));
+ ok1(p == haystack);
+ pc = memcheck(haystack, sizeof(haystack));
+ ok1(pc == haystack);
+ p = memcheck(p, sizeof(haystack));
+ ok1(p == haystack);
+ pc = memcheck(pc, sizeof(haystack));
+ ok1(pc == haystack);
+
+ /* This exits depending on whether all tests passed */
+ return exit_status();
+}
--- /dev/null
+#include "config.h"
+
+#include <assert.h>
+#include <ccan/mem/mem.h>
+
+int main(void)
+{
+ const char *haystack = "abcd\0efgh";
+ char *p;
+
+#ifdef FAIL
+#if !HAVE_TYPEOF
+#error "Can't fail without typeof"
+#else
+ /* Should catch const discard errors. */
+ p = memcheck(haystack, sizeof(haystack));
+#endif
+#else
+ p = memcheck((char *)haystack, sizeof(haystack));
+#endif
+
+ return p == haystack ? 0 : 1;
+}