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<?php function userland_func_get_arg($idx) { return isset(debug_backtrace()[1]['args'][$idx]) ? debug_backtrace()[1]['args'][$idx] : false; } function foo(&$arg) { $a = func_get_arg(0); $a = 'bar'; } function bar(&$arg) { $a = userland_func_get_arg(0); $a = 'bar'; } $foo = 'foo'; var_dump(foo($foo, 'bar')); var_dump($foo); $foo = 'foo'; var_dump(bar($foo, 'bar')); var_dump($foo);

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