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glibc  2.9
swapcontext.c
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00001 /* Copyright (C) 2001 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003      Contributed by David Mosberger-Tang <davidm@hpl.hp.com>.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include <ucontext.h>
00021 
00022 struct rv
00023   {
00024     long retval;
00025     long first_return;
00026   };
00027 
00028 extern struct rv __getcontext (ucontext_t *__ucp) __THROW;
00029 extern int __setcontext (__const ucontext_t *__ucp) __THROW;
00030 
00031 int
00032 __swapcontext (ucontext_t *oucp, const ucontext_t *ucp)
00033 {
00034   struct rv rv = __getcontext (oucp);
00035   if (rv.first_return)
00036     __setcontext (ucp);
00037   return 0;
00038 }
00039 
00040 weak_alias (__swapcontext, swapcontext)