Description:
------------
following codes in extension didn't work as expected:
....
 zend_fcall_info fci = {0};
 zend_fcall_info_cache fci_cache;
...
    if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s|f", &key, &klen, 
&fci, &fci_cache) {
         return;
     }

    if (!fci.size) {   
       // not a valid callback
    }


in PHP script:

php_ext_function("name", NULL);  

result in:
argument 2 not a valid callback...  

I haved tried set the arginfo with all_null.