Re: __toString() must return a string value

Johannes Schlüter writes: Hi! >> Why? Isn't it DateTime::format responsible to set string? > > It might return a NULL-zval in case it has problems passing the > parameter or in case of another error. What might return NULL zval? PHP_FUNCTION(date_format) { [...] RETURN_STRING(date_format(format, format_len, dateobj->time, dateobj->time->is_localtime), 0); } Can you give me a pointer where this method(function) returns NULL zval so I should really worry about in derived class? Of course, you are right, to avoid future segfaults when API change I should return zval. But, I started this thread to talk about this particular case. >> And, am I really responsible to set type of zval when passing it as >> in/out function argument? > > Yes. Can you explain why it works when I pass 'strv' initialized as NULL? Besides, isn't it very bad to initialize zval variable without knowing what method or function will do with it? OK, let's assume I initialize this zval with some zend type. Which one? Array, long, bool, object maybe? > Probably you should fetch a C book and e-read the chapter about > pointers. I do not think I have problems with C or understanding what pointer is or not. I started a thread @pecl, because I have problems understanding zend API, and I have been told it's the best place to talk about it. Zend/zend.h:#define INTERNAL_FUNCTION_PARAMETERS int ht, zval *return_value, zval **return_value_ptr, zval *this_ptr, int return_value_used TSRMLS_DC Isn't return_value a pointer? So what's the difference between zval *strv and zval *return_value ? Can you be so kind and suggest a solution (part of code or source file which uses it) to use return_value instead of duplicating 'strv' to return_value? Should it looks like this? MAKE_STD_ZVAL(return_value); Z_TYPE_P(return_value) = IS_STRING; zend_call_method_with_1_params(&zend_object, Z_OBJCE_P(zend_object), NULL, "format", &return_value, fmt); From spl extension: zval *rv; zend_call_method_with_1_params(&object, Z_OBJCE_P(object), &intern->fptr_offset_get, "offsetGet", &rv, offset); Clearly, rv is a pointer and not initialized as particular zend type. Piotras