PHP Error: Function name must be a string

This error typically occurs when you try to call a function dynamically, but the variable holding the function name is not a string. Common causes include uninitialized variables, variables set to null or integers, or functions that return the wrong type instead of a string.

Here is an example of code that would trigger this error:

PHP Error: Function name must be a string

<?php

$functionName = null; // or an uninitialized variable, or an integer
$functionName();

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To fix this error, ensure that the variable contains a valid string before calling it. You can verify the type or assign the correct string value:

Example of fixing PHP Error: Function name must be a string

<?php

$functionName = 'myFunction';
if (is_string($functionName)) {
    $functionName();
}

Alternatively, you can simply call the function directly by using its name as a string, like this:

Example of calling the function directly by using its name as a string in PHP

<?php

myFunction();