return false on invalid mode and don't segfault

diff --git a/ext/standard/string.c b/ext/standard/string.c
index fab460e265478ec455a4336ab3fb99b2109737f9..9ad5f74e1f2b139e17493710bf679fcc207a57d5 100644 (file)
--- a/ext/standard/string.c
+++ b/ext/standard/string.c
@@ -6465,6 +6465,7 @@ PHP_FUNCTION(count_chars)
                }
                if (UG(unicode) && mode != 1) {
                        php_error_docref(NULL TSRMLS_CC, E_WARNING, "Only mode=1 is supported with Unicode strings");
+                       RETURN_FALSE;
                }
        }