1  /* Copyright (C) 2001-2023 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  #include <ucontext.h>
      19  
      20  struct rv
      21    {
      22      long retval;
      23      long first_return;
      24    };
      25  
      26  extern struct rv __getcontext (ucontext_t *__ucp) __THROW;
      27  extern int __setcontext (const ucontext_t *__ucp) __THROW;
      28  
      29  int
      30  __swapcontext (ucontext_t *oucp, const ucontext_t *ucp)
      31  {
      32    struct rv rv = __getcontext (oucp);
      33    if (rv.first_return)
      34      __setcontext (ucp);
      35    return 0;
      36  }
      37  
      38  weak_alias (__swapcontext, swapcontext)