Why Does My PHP Code Throw a 'Cannot Pass Parameter 2 by Reference' Error and How Can I Fix It?

Resolving the "Cannot Pass Parameter 2 by Reference" Error in PHP

When working with PHP, you may encounter the following error:

Fatal error: Cannot pass parameter 2 by reference in /web/stud/openup/inactivatesession.php on line 13

This error indicates that your PHP code is attempting to pass the second parameter of a function or method by reference, but the parameter is not being correctly identified as a reference.

Understanding the Error

PHP's bind_param() method expects the second parameter to be a reference to a variable. However, in the code provided:

$update->bind_param("is", 0, $selectedDate); //LINE 13

The second parameter, 0, is being passed as an integer value, not a reference to a variable. This discrepancy causes the error.

Fixing the Error

To resolve this error, you need to pass a reference to a variable instead of the integer. This can be achieved by using the following code:

$a = 0;
$update->bind_param("is", $a, $selectedDate); //LINE 13

By assigning the integer value to a variable ($a) and then passing the reference of that variable, you ensure that the parameter is being passed by reference as required.

Additional Information

For a more thorough understanding of what is causing this error, refer to the PHP documentation on references: http://php.net/manual/en/language.references.pass.php

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