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<?php $v = 18; function f( &$p ) { $p = 36; return $p; } echo call_user_func('f', $v); // error: expecting reference variable
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Warning: f(): Argument #1 ($p) must be passed by reference, value given in /in/Ba7qZ on line 7 36
Output for 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33
Warning: Parameter 1 to f() expected to be a reference, value given in /in/Ba7qZ on line 7 36
Output for 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.38, 7.0.0 - 7.0.32
Warning: Parameter 1 to f() expected to be a reference, value given in /in/Ba7qZ on line 7
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.1 - 5.1.6, 5.2.0 - 5.2.17
36
Output for 5.1.0
Fatal error: fatal flex scanner internal error--end of buffer missed in /in/Ba7qZ on line 7
Process exited with code 255.

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