1 files changed, 1 insertions, 1 deletions

diff --git a/src/sp_wrapper.c b/src/sp_wrapper.c
index 6b6c5cd..22b1d88 100644
--- a/src/sp_wrapper.c
+++ b/src/sp_wrapper.c
@@ -180,7 +180,7 @@ PHP_FUNCTION(sp_stream_wrapper_register) {
   if (!protocol_name || wrapper_is_whitelisted(protocol_name)) {
 
     // reject manual loading of "php" wrapper
-    if (!strcasecmp(ZSTR_VAL(protocol_name), "php") && sp_php_stream_is_filtered()) {
+    if (protocol_name && !strcasecmp(ZSTR_VAL(protocol_name), "php") && sp_php_stream_is_filtered()) {
       return;
     }