1 files changed, 13 insertions, 11 deletions
diff --git a/src/wchar/mbrtowc.c b/src/wchar/mbrtowc.c
index 16e2a937..aa7c4803 100644
--- a/src/wchar/mbrtowc.c
+++ b/src/wchar/mbrtowc.c
@@ -1,27 +1,29 @@
-#if 0
-
 #include <wchar.h>
+#include "_wchar.h"
 
+GCC_SSE_HACK
 size_t mbrtowc(wchar_t * restrict pwc, const char * restrict s, size_t n, mbstate_t * restrict ps)
 {
+	static struct __mbstate_t internal = { 0 };
+	static mbstate_t ip = { &internal };
+
+	if (ps == NULL) {
+		ps = &ip;
+	}
+
 	SIGNAL_SAFE(0);
+	ASSERT_MBSTATE(ps, MBTOW, s, pwc);
 	/* TODO: overlap */
 
-	(void)ps; (void)pwc; (void)n;
-
 	if (s == NULL) {
-		s = "";
-		n = 1;
+		return mbrtowc(NULL, "", 1, ps);
 	}
 
-	/* TODO */
+	SET_MBSTATE(ps, MBTOW, s, pwc);
 
-	return 0;
+	return n;
 }
 
 /*
 STDC(199409)
 */
-
-
-#endif