The ReflectionParameter::allowsNull() function is an inbuilt function in PHP which is used to checks whether the parameter NULL is allowed or not.
Syntax:
bool ReflectionParameter::allowsNull ( void )
Parameters: This function does not accept any parameters.
Return Value: This function returns TRUE if NULL parameter is allowed else FALSE.
Below programs illustrate the ReflectionParameter::allowsNull() function in PHP:
Program 1:
<?php    // Initializing a user-defined class Company1 class Company1 {     public function GFG( Exception $Parameter){} }    // Initializing a subclass Company2 class Company2 extends Company1 { }    // Using the ReflectionParameter over the above class $A = new ReflectionParameter(['Company2', 'GFG'], 0);    // Calling the allowsNull() function $B = $A->allowsNull();    // Getting the boolean value TRUE if NULL // parameter is allowed else FALSE. var_dump($B); ?> |
Output:
bool(false)
Program 2:
<?php    // Initializing some user-defined classes class Department1 {     public function HR($Parameter1){} } class Department2 {     public function Coding( Exception $Parameter2, Exception $Parameter3){} } class Department3 {     public function Marketing($Parameter4, $Parameter5, $Parameter6){} }    // Using the ReflectionParameter over the above classes $A = new ReflectionParameter(['Department1', 'HR'], 0); $B = new ReflectionParameter(['Department2', 'Coding'], 1); $C = new ReflectionParameter(['Department3', 'Marketing'], 2);    // Calling the allowsNull() function and // getting the boolean value TRUE if NULL // parameter is allowed else FALSE. var_dump($A->allowsNull()); var_dump($B->allowsNull()); var_dump($C->allowsNull()); ?> |
Output:
bool(true) bool(false) bool(true)
Reference: https://www.php.net/manual/en/reflectionparameter.allowsnull.php
