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      1 /*
      2  * sched_setscheduler.c
      3  *
      4  * Description:
      5  * POSIX thread functions that deal with thread scheduling.
      6  *
      7  * --------------------------------------------------------------------------
      8  *
      9  *      Pthreads-win32 - POSIX Threads Library for Win32
     10  *      Copyright(C) 1998 John E. Bossom
     11  *      Copyright(C) 1999,2005 Pthreads-win32 contributors
     12  *
     13  *      Contact Email: rpj (at) callisto.canberra.edu.au
     14  *
     15  *      The current list of contributors is contained
     16  *      in the file CONTRIBUTORS included with the source
     17  *      code distribution. The list can also be seen at the
     18  *      following World Wide Web location:
     19  *      http://sources.redhat.com/pthreads-win32/contributors.html
     20  *
     21  *      This library is free software; you can redistribute it and/or
     22  *      modify it under the terms of the GNU Lesser General Public
     23  *      License as published by the Free Software Foundation; either
     24  *      version 2 of the License, or (at your option) any later version.
     25  *
     26  *      This library is distributed in the hope that it will be useful,
     27  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
     28  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     29  *      Lesser General Public License for more details.
     30  *
     31  *      You should have received a copy of the GNU Lesser General Public
     32  *      License along with this library in the file COPYING.LIB;
     33  *      if not, write to the Free Software Foundation, Inc.,
     34  *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
     35  */
     36 
     37 #include "pthread.h"
     38 #include "implement.h"
     39 #include "sched.h"
     40 
     41 int
     42 sched_setscheduler (pid_t pid, int policy)
     43 {
     44   /*
     45    * Win32 only has one policy which we call SCHED_OTHER.
     46    * However, we try to provide other valid side-effects
     47    * such as EPERM and ESRCH errors. Choosing to check
     48    * for a valid policy last allows us to get the most value out
     49    * of this function.
     50    */
     51   if (0 != pid)
     52     {
     53       int selfPid = (int) GetCurrentProcessId ();
     54 
     55       if (pid != selfPid)
     56 	{
     57 	  HANDLE h =
     58 	    OpenProcess (PROCESS_SET_INFORMATION, PTW32_FALSE, (DWORD) pid);
     59 
     60 	  if (NULL == h)
     61 	    {
     62 	      errno =
     63 		(GetLastError () ==
     64 		 (0xFF & ERROR_ACCESS_DENIED)) ? EPERM : ESRCH;
     65 	      return -1;
     66 	    }
     67 	  else
     68 	    CloseHandle(h);
     69 	}
     70     }
     71 
     72   if (SCHED_OTHER != policy)
     73     {
     74       errno = ENOSYS;
     75       return -1;
     76     }
     77 
     78   /*
     79    * Don't set anything because there is nothing to set.
     80    * Just return the current (the only possible) value.
     81    */
     82   return SCHED_OTHER;
     83 }
     84