Bug #65362 [Com]: strcmp null return missing from docs.

Edit report at https://bugs.php.net/bug.php?id=65362&edit=1 ID: 65362 Comment by: atli dot jonsson at ymail dot com Reported by: atli dot jonsson at ymail dot com Summary: strcmp null return missing from docs. Status: Not a bug Type: Bug Package: Scripting Engine problem PHP Version: 5.5.1 Block user comment: N Private report: N New Comment: Yes, I realize this is common behaviour, and not as such a bug in PHP. That is why I originally categorized this as a documentation bug. The problem isn't PHP's behaviour, it's that the documentation on the functions I mentioned is misleading about the return type. There is no mention of the possibility of a null return, and while you may get away with not mentioning this fact for most functions, in the case of these particular functions, it can easily lead to unpredictable and hard to find bugs. Previous Comments: ------------------------------------------------------------------------ [2013-08-18 20:32:25] johannes@php.net This is common PHP behavior and documented in a note here: http://php.net/functions.internal ------------------------------------------------------------------------ [2013-08-18 07:54:39] yohgaki@php.net Other functions such as strlen()/strncmp()/etc return null. I'm not sure the best behavior, but E_NOTICE/E_WARNING for invalid parameters are preferred. ------------------------------------------------------------------------ [2013-08-18 07:50:51] yohgaki@php.net I changed bug type since this is in Zend/zend_builtin_functions.c. Shouldn't it raise error for arrays? Currently, it simply returned. /* {{{ proto int strcmp(string str1, string str2) Binary safe string comparison */ ZEND_FUNCTION(strcmp) { char *s1, *s2; int s1_len, s2_len; if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "ss", &s1, &s1_len, &s2, &s2_len) == FAILURE) { return; } RETURN_LONG(zend_binary_strcmp(s1, s1_len, s2, s2_len)); } /* }}} */ ------------------------------------------------------------------------ [2013-07-30 23:36:30] atli dot jonsson at ymail dot com Description: ------------ strcmp, strncmp, strcasecmp and strncasecmp will all return NULL when either string parameter is of a type that is invalid for string conversions, like Arrays, Objects and Resources. However, the docs make no mention of this fact. (Aside from a comment.) As the 0 value returned for equal strings, and NULL returned for invalid comparisons, are equal when compared in a non-strict manner, this can lead to unexpected behaviour. There is a warning issued, but without clarification the above is still in no way obvious. Test script: --------------- <?php $arr = []; $str = "PHP is awesome!"; if (strcmp($arr, $str) == 0) { echo "Equal!"; // Ends up here. } else { echo "Not equal!"; } ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=65362&edit=1