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ReflectionParameter::getDefaultValueConstantName

PHP function Edit on GitHub ✎

(PHP 5 >= 5.4.6, PHP 7, PHP 8)

Returns the default value's constant name if default value is constant or null

Description

ReflectionParameter::getDefaultValueConstantName(): string|null

Returns the default value's constant name of the parameter of any user-defined or internal function or method, if default value is constant or null. If the parameter is not optional a ReflectionException will be thrown.

Parameters Parameters

Return Values

Returns string on success or null on failure.

Changelog

Version	Description
8.0.0	This method now allows getting the default values' constant names of built-in functions and built-in class methods. Previously, a `ReflectionException` was thrown.

Examples

Getting default values' constant names of function parameters

php

<?php
function foo($test, $bar = PHP_INT_MIN)
{
    echo $test . $bar;
}

$function = new ReflectionFunction('foo');

foreach ($function->getParameters() as $param) {
    echo 'Name: ' . $param->getName() . PHP_EOL;
    if ($param->isOptional()) {
        echo 'Default value: ' . $param->getDefaultValueConstantName() . PHP_EOL;
    }
    echo PHP_EOL;
}
?>

The above example will output:

output

Name: test

Name: bar
Default value: PHP_INT_MIN