Function name must be a string

Description

When calling a function dynamically, the name of the function, in the $method variable, must be a string, and the function must exist.

Some other scalars, such as integer, might be used as function name, although it will fail.

Example

<?php

$method = new stdClass;
$method();

?>

Solutions

• Only use string names for dynamic call to functions.

• Cast the variable to string before using it.

In more recent PHP versions, this error message is now Object of type %s is not callable.