diff --git a/include/string.h b/include/string.h
index fb373c88e39d..f0dc21814897 100644
--- a/include/string.h
+++ b/include/string.h
@@ -61,7 +61,9 @@ void	*memccpy(void * __restrict, const void * __restrict, int, size_t);
 void	*memchr(const void *, int, size_t) __pure;
 int	 memcmp(const void *, const void *, size_t) __pure;
 void	*memcpy(void * __restrict, const void * __restrict, size_t);
+#if __BSD_VISIBLE
 void	*memmem(const void *, size_t, const void *, size_t);
+#endif
 void	*memmove(void *, const void *, size_t);
 void	*memset(void *, int, size_t);
 #if __BSD_VISIBLE