include/set-hooks.h

   1 /* Macros for using symbol sets for running lists of functions.
   2    Copyright (C) 1994-2017 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _SET_HOOKS_H
  20 #define _SET_HOOKS_H 1
  21
  22 #define __need_size_t
  23 #include <stddef.h>
  24 #include <sys/cdefs.h>
  25
  26 #ifdef symbol_set_define
  27 /* Define a hook variable called NAME.  Functions put on this hook take
  28    arguments described by PROTO.  Use `text_set_element (NAME, FUNCTION)'
  29    from gnu-stabs.h to add a function to the hook.  */
  30
  31 # define DEFINE_HOOK(NAME, PROTO)               \
  32   typedef void __##NAME##_hook_function_t PROTO; \
  33   symbol_set_define (NAME)
  34
  35 # define DECLARE_HOOK(NAME, PROTO)              \
  36   typedef void __##NAME##_hook_function_t PROTO;\
  37   symbol_set_declare (NAME)
  38
  39 /* Run all the functions hooked on the set called NAME.
  40    Each function is called like this: `function ARGS'.  */
  41
  42 # define RUN_HOOK(NAME, ARGS)                                                 \
  43 do {                                                                          \
  44   void *const *ptr;                                                   \
  45   for (ptr = (void *const *) symbol_set_first_element (NAME);                 \
  46        ! symbol_set_end_p (NAME, ptr); ++ptr)                                 \
  47     (*(__##NAME##_hook_function_t *) *ptr) ARGS;                              \
  48 } while (0)
  49
  50 /* Define a hook variable with NAME and PROTO, and a function called RUNNER
  51    which calls each function on the hook in turn, with ARGS.  */
  52
  53 # define DEFINE_HOOK_RUNNER(name, runner, proto, args) \
  54 DEFINE_HOOK (name, proto); \
  55 extern void runner proto; void runner proto { RUN_HOOK (name, args); }
  56
  57 #else
  58
  59 /* The system does not provide necessary support for this.  */
  60 # define DEFINE_HOOK(NAME, PROTO)
  61
  62 # define DECLARE_HOOK(NAME, PROTO)
  63
  64 # define RUN_HOOK(NAME, ARGS)
  65
  66 # define DEFINE_HOOK_RUNNER(name, runner, proto, args)
  67
  68 #endif
  69
  70 #endif /* set-hooks.h */