PHP | ReflectionParameter isCallable() Function

The ReflectionParameter::isCallable() function is an inbuilt function in PHP which is used to return TRUE if the specified parameter is callable, FALSE otherwise.

Syntax:

bool ReflectionParameter::isCallable ( void )

Parameters: This function does not accept any parameters.

Return Value: This function returns TRUE if the specified parameter is callable, FALSE otherwise.

Below programs illustrate the ReflectionParameter::isCallable() function in PHP:
Program 1:

<?php

// Initializing a user-defined class Company1
class Company1
{
    public function GFG( callable $Parameter){}
}

// Initializing a subclass Company2
class Company2 extends Company1
{
}

// Using the ReflectionParameter over the above class
$A = new ReflectionParameter(['Company2', 'GFG'], 0);

// Calling the isCallable() function
$B = $A->isCallable();

// Getting TRUE if the specified parameter
// is callable, FALSE otherwise.
var_dump($B);
?>

Output:

bool(true)

Program 2:

<?php

// Initializing some user-defined classes
class Department1
{
    protected function HR( callable $Parameter1){}
}
class Department2
{
    final function Coding( $Parameter2, $Parameter3){}
}
class Department3
{
    function Marketing( sting $Parameter4,
       string $Parameter5, string $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 isCallable() function and
// getting TRUE if the specified parameter
// is callable, FALSE otherwise.
var_dump($A->isCallable());
var_dump($B->isCallable());
var_dump($C->isCallable());
?>

Output:

bool(true)
bool(false)
bool(false)

Reference: https://www.php.net/manual/en/reflectionparameter.iscallable.php