Description:
------------
Using a one-line Stored Procedure and a fairly simple PHP/PDO test calling a stored procedure, we should see the variable $retun_value change from "Before" to "After"...
All the MySQL Stored Procedure does is set the OUT parameter to the text "After"...

(** I'm using/tried PHP 5.0.5, 5.1.1 and 5.1.2 with MySQL 5.0.15 for the purpose of these tests)


MySQL v5.x:
==============
DELIMITER $$;
DROP PROCEDURE IF EXISTS `test`.`sp_returns_string`$$
CREATE PROCEDURE `test`.`sp_returns_string`(OUT vOutput varchar(32))
BEGIN
    SET vOutput = 'After';
END$$
DELIMITER ;$$
==============

Calling the SP from the command line does EXACTLY as expected, it returns the text "After"...
But it fails from PHP/PDO.

Variations i've tried on the code below include using a named parameter (e.g. :MyVar) but this fails just the same, I've tried NOT including the '@' but this fails with "OUT or INOUT argument 1 for routine test.sp_returns_string is not a variable", and various other changes including making the param in the stored proc an INOUT instead of OUT but nothing works... same error each time.


Reproduce code:
---------------
<?php

//First - check/load PDO!
if (!extension_loaded('pdo_mysql')) {
    // If not loaded we could try loading it manually
    $prefix = (PHP_SHLIB_SUFFIX == 'dll') ? 'php_' : '';
    if (!@dl($prefix . 'pdo_mysql.' . PHP_SHLIB_SUFFIX)) {
        die('pdo_mysql unavailable');
    }
}

$DB_Con = "mysql:host=localhost;dbname=test";
$db = new PDO($DB_Con, 'root', 'password', aray());

$return_value = 'Before';
print "Return_Value = $return_value<br/><br/>\r\n";
$stmt = $db->prepare("CALL sp_returns_string(@?)");
$stmt->bindParam(1, $return_value, PDO::PARAM_STR, 32);
$stmt->execute();
print "Return_Value = $return_value<br/><br/>\r\n";
?>

Expected result:
----------------
Return_Value = Before
Return_Value = After

Actual result:
--------------
Return_Value = Before
Return_Value = Before