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

   1 /*
   2  * errno.c
   3  *
   4  * Description:
   5  * This translation unit implements routines associated with spawning a new
   6  * thread.
   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 #if defined(NEED_ERRNO)
  39
  40 #include "pthread.h"
  41 #include "implement.h"
  42
  43 static int reallyBad = ENOMEM;
  44
  45 /*
  46  * Re-entrant errno.
  47  *
  48  * Each thread has it's own errno variable in pthread_t.
  49  *
  50  * The benefit of using the pthread_t structure
  51  * instead of another TSD key is TSD keys are limited
  52  * on Win32 to 64 per process. Secondly, to implement
  53  * it properly without using pthread_t you'd need
  54  * to dynamically allocate an int on starting the thread
  55  * and store it manually into TLS and then ensure that you free
  56  * it on thread termination. We get all that for free
  57  * by simply storing the errno on the pthread_t structure.
  58  *
  59  * MSVC and Mingw32 already have their own thread-safe errno.
  60  *
  61  * #if defined( _REENTRANT ) || defined( _MT )
  62  * #define errno *_errno()
  63  *
  64  * int *_errno( void );
  65  * #else
  66  * extern int errno;
  67  * #endif
  68  *
  69  */
  70
  71 int *
  72 _errno (void)
  73 {
  74   pthread_t self;
  75   int *result;
  76
  77   if ((self = pthread_self ()).p == NULL)
  78     {
  79       /*
  80        * Yikes! unable to allocate a thread!
  81        * Throw an exception? return an error?
  82        */
  83       result = &reallyBad;
  84     }
  85   else
  86     {
  87       result = (int *)(&self.p->exitStatus);
  88     }
  89
  90   return (result);
  91
  92 }                               /* _errno */
  93
  94 #endif /* (NEED_ERRNO) */