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run code in 300+ PHP versions simultaneously
<?php function ref( &$ref ) { var_dump( $ref ); } $func = 'ref'; $foo = 'native'; ref( $foo ); $foo = 'variable'; $func( $foo ); $foo = 'call_user_func_array'; call_user_func_array( $func, array( &$foo ) ); $foo = 'call_user_func'; call_user_func( $func, $foo );

preferences:
53.5 ms | 402 KiB | 5 Q