PHP error handling functions - set_error_handler()

Last update on May 28 2022 12:34:00 (UTC/GMT +8 hours)

Description

The set_error_handler() function is used to set a user-defined error handling function.

Version:

PHP 4.0.1, PHP 5

Syntax:

set_error_handler (error_handler, error_types)

Parameter:

Parameters	Description	Required / Optional	Type
error_handler	Specifies the function to be run at errors. Contains : errorno - An integer indicating the level of the error. errstr - A string which contains the error message. errfile - A string which contains the filename that the error was raised in. This is optional. errline - An integer indicating the line number the error was raised at. This is optional. errcontext - This is an array which contains all the variables that existed in the scope the error was triggered in. This is optional.	Required	callback
error_types	Purpose of this parameter is to mask the triggering of the error_handler function resembling the error_reporting ini setting controls which are to be shown. If not used, error_handler is called for every error irrespective of the setting of the error_reporting setting.	Required	integer

Return Values

The function returns a string which contains the previously defined error handler. But it returns NULL if the built-in error handler is used instead of a user defined one. In the case of an error resembling to invalid callback, the function returns NULL. If the user defined error handler used previously was a class method, the function returns an indexed array containing the name of the class and method.

Example :

 <?php
    function w3r_notice($no, $str, $file, $line) {
        echo "Encountered notice $no in $file, line $line: $str\n";
    }
    function func_error($num, $str, $file, $line) {
        echo "Encountered error $num in $file, line $line: $str\n";
    }
    set_error_handler("w3r_notice", E_NOTICE);
    set_error_handler("w3r_error", E_ERROR);
    echo $demo;
?>

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC