diff --git a/main/rfc1867.c b/main/rfc1867.c
index a5984830eda..4feb7f61aa2 100644
--- a/main/rfc1867.c
+++ b/main/rfc1867.c
@@ -827,7 +827,7 @@ SAPI_API SAPI_POST_HANDLER_FUNC(rfc1867_post_handler)
 			}
 
 #if HAVE_MBSTRING
-			s = mbstr_strrchr(filename, '\\');
+			s = mbstr_strrchr(filename, '\\' TSRMLS_CC);
 #else
 			s = strrchr(filename, '\\');
 #endif