diff --git a/ext/gd/gd.c b/ext/gd/gd.c
index dc706d53b00..620490fa954 100644
--- a/ext/gd/gd.c
+++ b/ext/gd/gd.c
@@ -1778,7 +1778,7 @@ static void _php_image_output(INTERNAL_FUNCTION_PARAMETERS, int image_type, char
 		char  buf[4096];
 		char *path;
 
-		tmp = php_open_temporary_file("", "", &path TSRMLS_CC);
+		tmp = php_open_temporary_file(NULL, NULL, &path TSRMLS_CC);
 		if (tmp == NULL) {
 			php_error_docref(NULL TSRMLS_CC, E_WARNING, "Unable to open temporary file");
 			RETURN_FALSE;
diff --git a/main/php_open_temporary_file.c b/main/php_open_temporary_file.c
index b64ddc8dfea..9e602f21043 100644
--- a/main/php_open_temporary_file.c
+++ b/main/php_open_temporary_file.c
@@ -98,6 +98,7 @@ static int php_do_open_temporary_file(const char *path, const char *pfx, char **
 {
 	char *trailing_slash;
 	char *opened_path;
+	int path_len = 0;
 	int fd = -1;
 #ifndef HAVE_MKSTEMP
 	int open_flags = O_CREAT | O_TRUNC | O_RDWR
@@ -111,11 +112,13 @@ static int php_do_open_temporary_file(const char *path, const char *pfx, char **
 		return -1;
 	}
 
+	path_len = strlen(path);
+
 	if (!(opened_path = emalloc(MAXPATHLEN))) {
 		return -1;
 	}
 
-	if (IS_SLASH(path[strlen(path)-1])) {
+	if (!path_len || IS_SLASH(path[path_len - 1])) {
 		trailing_slash = "";
 	} else {
 		trailing_slash = "/";