(PHP 5 >= 5.4.6, PHP 7)
ReflectionParameter::getDefaultValueConstantName — Returns the default value's constant name if default value is constant or null
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.
此函数没有参数。
Returns string on success or NULL on failure.
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
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.