stdlib/ucontext.h

   1 /* Copyright (C) 1997-2021 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 /* System V ABI compliant user-level context switching support.  */
  19
  20 #ifndef _UCONTEXT_H
  21 #define _UCONTEXT_H     1
  22
  23 #include <features.h>
  24
  25 /* Get definition of __INDIRECT_RETURN.  */
  26 #include <bits/indirect-return.h>
  27
  28 /* Get machine dependent definition of data structures.  */
  29 #include <sys/ucontext.h>
  30
  31 __BEGIN_DECLS
  32
  33 /* Get user context and store it in variable pointed to by UCP.  */
  34 extern int getcontext (ucontext_t *__ucp) __THROWNL;
  35
  36 /* Set user context from information of variable pointed to by UCP.  */
  37 extern int setcontext (const ucontext_t *__ucp) __THROWNL;
  38
  39 /* Save current context in context variable pointed to by OUCP and set
  40    context from variable pointed to by UCP.  */
  41 extern int swapcontext (ucontext_t *__restrict __oucp,
  42                         const ucontext_t *__restrict __ucp)
  43   __THROWNL __INDIRECT_RETURN;
  44
  45 /* Manipulate user context UCP to continue with calling functions FUNC
  46    and the ARGC-1 parameters following ARGC when the context is used
  47    the next time in `setcontext' or `swapcontext'.
  48
  49    We cannot say anything about the parameters FUNC takes; `void'
  50    is as good as any other choice.  */
  51 extern void makecontext (ucontext_t *__ucp, void (*__func) (void),
  52                          int __argc, ...) __THROW;
  53
  54 __END_DECLS
  55
  56 #endif /* ucontext.h */