| 1 | /* GNU Objective C Runtime nil receiver function
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| 2 | Copyright (C) 1993, 1995, 1996, 2002 Free Software Foundation, Inc.
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| 3 | Contributed by Kresten Krab Thorup
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| 4 |
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| 5 | This file is part of GNU CC.
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| 6 |
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| 7 | GNU CC is free software; you can redistribute it and/or modify it under the
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| 8 | terms of the GNU General Public License as published by the Free Software
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| 9 | Foundation; either version 2, or (at your option) any later version.
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| 10 |
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| 11 | GNU CC is distributed in the hope that it will be useful, but WITHOUT ANY
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| 12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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| 13 | FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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| 14 | details.
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| 15 |
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| 16 | You should have received a copy of the GNU General Public License along with
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| 17 | GNU CC; see the file COPYING. If not, write to the Free Software
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| 18 | Foundation, 59 Temple Place - Suite 330,
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| 19 | Boston, MA 02111-1307, USA. */
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| 20 |
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| 21 | /* As a special exception, if you link this library with files compiled with
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| 22 | GCC to produce an executable, this does not cause the resulting executable
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| 23 | to be covered by the GNU General Public License. This exception does not
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| 24 | however invalidate any other reasons why the executable file might be
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| 25 | covered by the GNU General Public License. */
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| 26 |
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| 27 | /* This is the nil method, the function that is called when the receiver
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| 28 | of a method is nil */
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| 29 |
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| 30 | #include "runtime.h"
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| 31 |
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| 32 | /* When the receiver of a method invocation is nil, the runtime
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| 33 | returns nil_method() as the method implementation. This function
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| 34 | will be casted to whatever function was supposed to be executed to
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| 35 | execute that method (that function will take an id, followed by a
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| 36 | SEL, followed by who knows what arguments, depends on the method),
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| 37 | and executed.
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| 38 |
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| 39 | For this reason, nil_method() should be a function which can be
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| 40 | called in place of any function taking an 'id' argument followed by
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| 41 | a 'SEL' argument, followed by zero, or one, or any number of
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| 42 | arguments (both a fixed number, or a variable number !).
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| 43 |
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| 44 | There is no "proper" implementation of such a nil_method function
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| 45 | in C, however in all existing implementations it does not matter
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| 46 | when extra arguments are present, so we can simply create a function
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| 47 | taking a receiver and a selector, and all other arguments will be
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| 48 | ignored. :-)
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| 49 | */
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| 50 |
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| 51 | id
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| 52 | nil_method (id receiver, SEL op __attribute__ ((__unused__)))
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| 53 | {
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| 54 | return receiver;
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| 55 | }
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