The Dev Pages » PHP http://www.n8williams.com/devblog A knowledge base for simple (and beyond) web applications development Mon, 07 Nov 2011 08:31:27 +0000 http://wordpress.org/?v=2.8.6 en hourly 1 Prepared statement errors with PHP 5.3 and mysqli. call_user_func_array returns null. Type error? http://www.n8williams.com/devblog/php/prepared-statement-errors-with-php-5-3-and-mysqli-call_user_func_array-returns-null http://www.n8williams.com/devblog/php/prepared-statement-errors-with-php-5-3-and-mysqli-call_user_func_array-returns-null#comments Thu, 10 Sep 2009 23:04:36 +0000 Nate Admin http://www.n8williams.com/devblog/?p=144 Prepared statements using mysqli seems to be having issues with PHP 5.3. I kept getting null from a prepared statement command that worked fine in PHP 5.2, namely, the mysqli_stmt_bind_param

Null means that the array you passed didn’t match the function signature.

The following worked in php 5.2, but when I updated my Mac to Snow Leopard (PHP 5.3 included) the following function stopped working

call_user_func_array(’mysqli_stmt_bind_param’, array($stmt,’isis’,$args));

I kept getting a null return value (note – different than false). See bottom of the following bug:  http://bugs.php.net/bug.php?id=47554&edit=1

"Returns the function result, NULL for an invalid callback, and FALSE
for all other errors."

Toying with the array (translates to method signature of the callback function) passed to call_user_func_array was key. After much head banging (on desk) and much head banging (to music) I found that the following made my one specific test query work:

call_user_func_array(’mysqli_stmt_bind_param’, array($stmt,’isis’,(int) $args[2],(string) $args[3],(int) $args[4],(string) $args[5]));

I wonder if the library that mysqli uses is in c (so that mysqli_stmt_bind_param is eventually run at a level where typing needs to be determined), and is requiring typed values that the php is screwing up somewhere in the translation. Or on the mysqli level. And I wonder what other explanations there could be for this behavior.

Usually when code is this buggy it is a developer’s coding errors, but someday I hope to run into a bug that isn’t my fault. On second thought, finding a bug in your development language probably causes a lot more pain in trying to figure it out, so I’m not sure that would be much of an accomplishment.

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