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glibc  2.9
setpgid.c
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00001 /* Copyright (C) 1993,1994,1995,1996,1997,2002 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <errno.h>
00020 #include <unistd.h>
00021 #include <hurd.h>
00022 #include <hurd/port.h>
00023 
00024 /* Set the process group ID of the process matching PID to PGID.
00025    If PID is zero, the current process's process group ID is set.
00026    If PGID is zero, the process ID of the process is used.  */
00027 int
00028 __setpgid (pid, pgid)
00029      pid_t pid;
00030      pid_t pgid;
00031 {
00032   error_t err;
00033   unsigned int stamp;
00034 
00035   stamp = _hurd_pids_changed_stamp; /* Atomic fetch.  */
00036 
00037   if (err = __USEPORT (PROC, __proc_setpgrp (port, pid, pgid)))
00038     return __hurd_fail (err);
00039 
00040   if (pid == 0 || pid == _hurd_pid)
00041     /* Synchronize with the signal thread to make sure we have
00042        received and processed proc_newids before returning to the user.  */
00043     while (_hurd_pids_changed_stamp == stamp)
00044       {
00045 #ifdef noteven
00046        /* XXX we have no need for a mutex, but cthreads demands one.  */
00047        __condition_wait (&_hurd_pids_changed_sync, NULL);
00048 #else
00049        __swtch_pri(0);
00050 #endif
00051       }
00052 
00053   return 0;
00054 
00055 }
00056 libc_hidden_def (__setpgid)
00057 weak_alias (__setpgid, setpgid)