1 files changed, 9 insertions, 0 deletions
diff --git a/src/malloc/oldmalloc/malloc_usable_size.c b/src/malloc/oldmalloc/malloc_usable_size.c
new file mode 100644
index 00000000..672b518a
--- /dev/null
+++ b/src/malloc/oldmalloc/malloc_usable_size.c
@@ -0,0 +1,9 @@
+#include <malloc.h>
+#include "malloc_impl.h"
+ 
+hidden void *(*const __realloc_dep)(void *, size_t) = realloc;
+
+size_t malloc_usable_size(void *p)
+{
+	return p ? CHUNK_SIZE(MEM_TO_CHUNK(p)) - OVERHEAD : 0;
+}