【php8上級/準上級試験】模擬問題解説 問題28 function_exists()

function func($a, $b) {
    echo __FUNCTION__, PHP_EOL;
    var_dump($a, $b);
    echo PHP_EOL;
}

function func2(&$v) {
    $v[] = 999;
}

class Hoge {
    public function func1($a) {
        echo __METHOD__, PHP_EOL;
        var_dump($a);
        echo PHP_EOL;
    }

    public static function func2($a) {
        echo __METHOD__, PHP_EOL;
        var_dump(get_called_class(), $a);
        echo PHP_EOL;
    }
}

call_user_func('func', 1, 2);
call_user_func_array('func', ['var', 'val']);

$obj = new Hoge();
call_user_func([$obj, 'func1'], 999);
call_user_func([Hoge::class, 'func2'], 'val');

$v = [];
call_user_func('func2', $v);
var_dump($v);

func
int(1)
int(2)

func
string(3) "var"
string(3) "val"

Hoge::func1
int(999)

Hoge::func2
string(4) "Hoge"
string(3) "val"

Warning: func2(): Argument #1 ($v) must be passed by reference, value given in ...
array(0) {
}

class Hoge {
    public static function func() {
        echo __METHOD__, PHP_EOL;
        var_dump(get_called_class());
        echo PHP_EOL;
    }
}

class Foo extends Hoge {
    public static function callMethod() {
        forward_static_call(['Hoge', 'func']);
        echo PHP_EOL;
        call_user_func(['Hoge', 'func']);
    }
}

Foo::callMethod();
forward_static_call(['Hoge', 'func']);

class Hoge {
    public function func() {
    }
}

function foo() {
}

$fn = function($v) {
    var_dump( $v, function_exists($v) );
    echo PHP_EOL;
};

$fn( [Hoge:class, 'func'] );
$fn( 'foo' );
$fn( 'function_exists' );
$fn( 'echo' );
$fn( 'dummy' );

array(2) {
  [0]=>
  string(4) "Hoge"
  [1]=>
  string(4) "func"
}
bool(true)

string(3) "foo"
bool(true)

string(15) "function_exists"
bool(true)

string(4) "echo"
bool(true)

string(5) "dummy"
bool(false)

register_shutdown_function(function() {
    echo "register_shutdown_function 1", PHP_EOL;
});
register_shutdown_function(function($v) {
    echo "register_shutdown_function 2 {$v}", PHP_EOL;
}, 'val');
register_shutdown_function(function() {
    echo "register_shutdown_function 3", PHP_EOL;
    exit;
});
register_shutdown_function(function() {
    echo "register_shutdown_function 4", PHP_EOL;
});

echo "start", PHP_EOL;
exit;