Re: __toString() must return a string value

On Sat, 2009-02-21 at 13:15 +0100, Piotr Pokora wrote: > Hi! > > Method implementation looks like this (for DateTime derived): > > static PHP_METHOD(midgard_datetime, __toString) > { > if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "") == FAILURE) > return; > > /* Prepare DateTime::format argument */ > zval *fmt; > MAKE_STD_ZVAL(fmt); > ZVAL_STRING(fmt, "c", 0); > > /* Invoke Datetime::format */ > zval *zend_object = getThis(); > > zend_call_method_with_1_params(&zend_object, > Z_OBJCE_P(zend_object), NULL, "format", &return_value, fmt); here you are passing the address of your local variable "return_value" so zend_call_method will change the pointer. It's basically like doing return_value = 23; This change has no effect on the caller of your function it will still see a NULL-zval. You might try using return_value_ptr, which is part of the PHP_FUNCTION signature - I never used that though :-) [...] > zval *strv = NULL; > zend_call_method_with_1_params(&zend_object, Z_OBJCE_P(zend_object), > NULL, "format", &strv, fmt); > RETURN_STRING(Z_STRVAL_P(strv), 0); When doing this you should check they type. You might also use RETURN_ZVAL() if you don't care for the type. johannes