1 /* GNU Objective C Runtime nil receiver function 2 Copyright (C) 1993-2019 Free Software Foundation, Inc. 3 Contributed by Kresten Krab Thorup 4 5 This file is part of GCC. 6 7 GCC is free software; you can redistribute it and/or modify it under the 8 terms of the GNU General Public License as published by the Free Software 9 Foundation; either version 3, or (at your option) any later version. 10 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 13 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 14 details. 15 16 Under Section 7 of GPL version 3, you are granted additional 17 permissions described in the GCC Runtime Library Exception, version 18 3.1, as published by the Free Software Foundation. 19 20 You should have received a copy of the GNU General Public License and 21 a copy of the GCC Runtime Library Exception along with this program; 22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 <http://www.gnu.org/licenses/>. */ 24 25 26 /* This is the nil method, the function that is called when the receiver 27 of a method is nil */ 28 29 #include "objc-private/common.h" 30 #include "objc/objc.h" 31 32 /* When the receiver of a method invocation is nil, the runtime 33 returns nil_method() as the method implementation. This function 34 will be casted to whatever function was supposed to be executed to 35 execute that method (that function will take an id, followed by a 36 SEL, followed by who knows what arguments, depends on the method), 37 and executed. 38 39 For this reason, nil_method() should be a function which can be 40 called in place of any function taking an 'id' argument followed by 41 a 'SEL' argument, followed by zero, or one, or any number of 42 arguments (both a fixed number, or a variable number !). 43 44 There is no "proper" implementation of such a nil_method function 45 in C, however in all existing implementations it does not matter 46 when extra arguments are present, so we can simply create a function 47 taking a receiver and a selector, and all other arguments will be 48 ignored. :-) 49 */ 50 51 id 52 nil_method (id receiver, SEL op __attribute__ ((__unused__))) 53 { 54 return receiver; 55 } 56