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1 /* GNU Objective C Runtime nil receiver function
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2 Copyright (C) 1993-2020 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 GCC.
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6
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7 GCC 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 3, or (at your option) any later version.
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10
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11 GCC 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 Under Section 7 of GPL version 3, you are granted additional
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17 permissions described in the GCC Runtime Library Exception, version
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18 3.1, as published by the Free Software Foundation.
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19
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20 You should have received a copy of the GNU General Public License and
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21 a copy of the GCC Runtime Library Exception along with this program;
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22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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23 <http://www.gnu.org/licenses/>. */
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24
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25
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26 /* This is the nil method, the function that is called when the receiver
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27 of a method is nil */
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28
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29 #include "objc-private/common.h"
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30 #include "objc/objc.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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