libobjc/objc/message.h

   1 /* GNU Objective C Runtime messaging declarations
   2    Copyright (C) 1993, 1995, 1996, 2004, 2009,
   3    2010 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 Under Section 7 of GPL version 3, you are granted additional
  18 permissions described in the GCC Runtime Library Exception, version
  19 3.1, as published by the Free Software Foundation.
  20
  21 You should have received a copy of the GNU General Public License and
  22 a copy of the GCC Runtime Library Exception along with this program;
  23 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 <http://www.gnu.org/licenses/>.  */
  25
  26 #ifndef __objc_message_INCLUDE_GNU
  27 #define __objc_message_INCLUDE_GNU
  28
  29 #ifdef __cplusplus
  30 extern "C" {
  31 #endif
  32
  33 #include "objc.h"
  34 #include "objc-decls.h"
  35
  36 /* This file includes declarations of the messaging functions and
  37    types.
  38 */
  39
  40 /* Compatibility note: the messaging function is one area where the
  41    GNU runtime and the Apple/NeXT runtime differ significantly.  If
  42    you can, it is recommended that you use higher-level facilities
  43    (provided by a Foundation library such as GNUstep Base) to perform
  44    forwarding or other advanced messaging tricks.
  45 */
  46
  47 typedef void* retval_t;         /* return value */
  48 typedef void(*apply_t)(void);   /* function pointer */
  49 typedef union arglist {
  50   char *arg_ptr;
  51   char arg_regs[sizeof (char*)];
  52 } *arglist_t;                   /* argument frame */
  53
  54 objc_EXPORT IMP objc_msg_lookup(id receiver, SEL op);
  55
  56 /*
  57  * Structure used when a message is send to a class's super class.
  58  * The compiler generates one of these structures and passes it to
  59  * objc_msg_lookup_super.
  60  */
  61 typedef struct objc_super {
  62   id      self;       /* Id of the object sending the message. */
  63 #ifdef __cplusplus
  64   /* The new version of the API will always use 'super_class'.  */
  65   Class super_class;
  66 #else
  67   Class class;        /* Object's super class. */
  68 #endif
  69 } Super, *Super_t;
  70
  71 objc_EXPORT IMP objc_msg_lookup_super(Super_t super, SEL sel);
  72
  73 objc_EXPORT retval_t objc_msg_sendv(id, SEL, arglist_t);
  74
  75 /*
  76  * Hooks for method forwarding. This makes it easy to substitute a
  77  * library, such as ffcall, that implements closures, thereby avoiding
  78  * gcc's __builtin_apply problems.  __objc_msg_forward2's result will
  79  * be preferred over that of __objc_msg_forward if both are set and
  80  * return non-NULL.
  81  *
  82  * TODO: The API should define objc_set_msg_forward_handler () or
  83  * similar instead of these hooks.
  84  */
  85 objc_EXPORT IMP (*__objc_msg_forward)(SEL);
  86 objc_EXPORT IMP (*__objc_msg_forward2)(id, SEL);
  87
  88 #ifdef __cplusplus
  89 }
  90 #endif
  91
  92 #endif /* not __objc_message_INCLUDE_GNU */