ReflectionParameter::getDefaultValueConstantName

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

ReflectionParameter::getDefaultValueConstantName — Returns the default value's constant name if default value is constant or null

说明

public ReflectionParameter::getDefaultValueConstantName(): ?string

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.

参数

此函数没有参数。

返回值

Returns string on success or null on failure.

更新日志

版本	说明
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.

示例

示例 #1 Getting default values' constant names of function parameters

<?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;
}
?>

以上示例会输出：

Name: test

Name: bar
Default value: PHP_INT_MIN

参见

ReflectionParameter::isOptional() - Checks if optional
ReflectionParameter::isDefaultValueConstant() - Returns whether the default value of this parameter is a constant
ReflectionParameter::getDefaultValue() - Gets default parameter value

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