1 files changed, 19 insertions, 0 deletions
diff --git a/missing/memcmp.c b/missing/memcmp.c
new file mode 100644
index 0000000000..9657e6c372
--- /dev/null
+++ b/missing/memcmp.c
@@ -0,0 +1,19 @@
+/* public domain rewrite of memcmp(3) */
+
+#include "ruby/missing.h"
+#include <stddef.h>
+
+int
+memcmp(const void *s1, const void *s2, size_t len)
+{
+    register unsigned char *a = (unsigned char*)s1;
+    register unsigned char *b = (unsigned char*)s2;
+    register int tmp;
+
+    for (; len; --len) {
+	tmp = *a++ - *b++;
+	if (tmp)
+	    return tmp;
+    }
+    return 0;
+}