<?php

  function test () {
    $argc = func_num_args();
    for ($i = 0; $i < $argc; $i++) global ${func_get_arg($i)};
    echo "Inside function: \$var = $var; \$i = $i; \$arg = $arg;\n";
  }

  $i = 5;
  $var = 1;
  $arg = 'value';

  echo "Before function: \$var = $var; \$i = $i; \$arg = $arg;\n";
  test('var', 'i', 'arg');
  echo "After function: \$var = $var; \$i = $i; \$arg = $arg;\n";

Before function: $var = 1; $i = 5; $arg = value;
Inside function: $var = 1; $i = 6; $arg = ;
After function: $var = 1; $i = 6; $arg = value;