ReflectionParameter::getDefaultValueConstantName

(PHP 5 >= 5.4.6, PHP 7)

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

说明

public ReflectionParameter::getDefaultValueConstantName ( void ) : string

Returns the default value's constant name of the parameter of a user-defined 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.

范例

Example #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;
}
?>

以上例程会输出：

Name: test

Name: bar
Default value: PHP_INT_MIN

注释

Note:

Due to implementation details, it is not possible to get the default value of built-in functions or methods of built-in classes. Trying to do this will result a ReflectionException being thrown.

参见