native_client_sdk/src/libraries/third_party/pthreads-win32/ptw32_getprocessors.c

   1 /*
   2  * ptw32_getprocessors.c
   3  *
   4  * Description:
   5  * This translation unit implements routines which are private to
   6  * the implementation and may be used throughout it.
   7  *
   8  * --------------------------------------------------------------------------
   9  *
  10  *      Pthreads-win32 - POSIX Threads Library for Win32
  11  *      Copyright(C) 1998 John E. Bossom
  12  *      Copyright(C) 1999,2005 Pthreads-win32 contributors
  13  *
  14  *      Contact Email: rpj@callisto.canberra.edu.au
  15  *
  16  *      The current list of contributors is contained
  17  *      in the file CONTRIBUTORS included with the source
  18  *      code distribution. The list can also be seen at the
  19  *      following World Wide Web location:
  20  *      http://sources.redhat.com/pthreads-win32/contributors.html
  21  *
  22  *      This library is free software; you can redistribute it and/or
  23  *      modify it under the terms of the GNU Lesser General Public
  24  *      License as published by the Free Software Foundation; either
  25  *      version 2 of the License, or (at your option) any later version.
  26  *
  27  *      This library is distributed in the hope that it will be useful,
  28  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  30  *      Lesser General Public License for more details.
  31  *
  32  *      You should have received a copy of the GNU Lesser General Public
  33  *      License along with this library in the file COPYING.LIB;
  34  *      if not, write to the Free Software Foundation, Inc.,
  35  *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  36  */
  37
  38 #include "pthread.h"
  39 #include "implement.h"
  40
  41
  42 /*
  43  * ptw32_getprocessors()
  44  *
  45  * Get the number of CPUs available to the process.
  46  *
  47  * If the available number of CPUs is 1 then pthread_spin_lock()
  48  * will block rather than spin if the lock is already owned.
  49  *
  50  * pthread_spin_init() calls this routine when initialising
  51  * a spinlock. If the number of available processors changes
  52  * (after a call to SetProcessAffinityMask()) then only
  53  * newly initialised spinlocks will notice.
  54  */
  55 int
  56 ptw32_getprocessors (int *count)
  57 {
  58   DWORD_PTR vProcessCPUs;
  59   DWORD_PTR vSystemCPUs;
  60   int result = 0;
  61
  62 #if defined(NEED_PROCESS_AFFINITY_MASK)
  63
  64   *count = 1;
  65
  66 #else
  67
  68   if (GetProcessAffinityMask (GetCurrentProcess (),
  69                               &vProcessCPUs, &vSystemCPUs))
  70     {
  71       DWORD_PTR bit;
  72       int CPUs = 0;
  73
  74       for (bit = 1; bit != 0; bit <<= 1)
  75         {
  76           if (vProcessCPUs & bit)
  77             {
  78               CPUs++;
  79             }
  80         }
  81       *count = CPUs;
  82     }
  83   else
  84     {
  85       result = EAGAIN;
  86     }
  87
  88 #endif
  89
  90   return (result);
  91 }