text: /*
      Copyright 2005-2009 Intel Corporation.  All Rights Reserved.
  
      This file is part of Threading Building Blocks.
  
      Threading Building Blocks is free software; you can redistribute it
      and/or modify it under the terms of the GNU General Public License
      version 2 as published by the Free Software Foundation.
  
      Threading Building Blocks is distributed in the hope that it will be
      useful, but WITHOUT ANY WARRANTY; without even the implied warranty
      of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      GNU General Public License for more details.
  
      You should have received a copy of the GNU General Public License
      along with Threading Building Blocks; if not, write to the Free Software
      Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  
      As a special exception, you may use this file as part of a free software
      library without restriction.  Specifically, if other files instantiate
      templates or use macros or inline functions from this file, or you compile
      this file and link it with other files to produce an executable, this
      file does not by itself cause the resulting executable to be covered by
      the GNU General Public License.  This exception does not however
      invalidate any other reasons why the executable file might be covered by
      the GNU General Public License.
  */
  
  #ifndef __TBB_machine_H
  #error Do not include this file directly; include tbb_machine.h instead
  #endif
  
  #include <stdint.h>
  #include <unistd.h>
  #include <sched.h>
  
  // Definition of __TBB_Yield()
  #define __TBB_Yield()  sched_yield()
  
  /* Futex definitions */
  #include <sys/syscall.h>
  
  #if defined(SYS_futex)
  
  #define __TBB_USE_FUTEX 1
  #include <limits.h>
  #include <errno.h>
  // Unfortunately, some versions of Linux do not have a header that defines FUTEX_WAIT and FUTEX_WAKE.
  
  #ifdef FUTEX_WAIT
  #define __TBB_FUTEX_WAIT FUTEX_WAIT
  #else
  #define __TBB_FUTEX_WAIT 0
  #endif
  
  #ifdef FUTEX_WAKE
  #define __TBB_FUTEX_WAKE FUTEX_WAKE
  #else
  #define __TBB_FUTEX_WAKE 1
  #endif
  
  #ifndef __TBB_ASSERT
  #error machine specific headers must be included after tbb_stddef.h
  #endif
  
  namespace tbb {
  
  namespace internal {
  
  inline int futex_wait( void *futex, int comparand ) {
      int r = ::syscall( SYS_futex,futex,__TBB_FUTEX_WAIT,comparand,NULL,NULL,0 );
  #if TBB_USE_ASSERT
      int e = errno;
      __TBB_ASSERT( r==0||r==EWOULDBLOCK||(r==-1&&(e==EAGAIN||e==EINTR)), "futex_wait failed." );
  #endif /* TBB_USE_ASSERT */
      return r;
  }
  
  inline int futex_wakeup_one( void *futex ) {
      int r = ::syscall( SYS_futex,futex,__TBB_FUTEX_WAKE,1,NULL,NULL,0 );
      __TBB_ASSERT( r==0||r==1, "futex_wakeup_one: more than one thread woken up?" );
      return r;
  }
  
  inline int futex_wakeup_all( void *futex ) {
      int r = ::syscall( SYS_futex,futex,__TBB_FUTEX_WAKE,INT_MAX,NULL,NULL,0 );
      __TBB_ASSERT( r>=0, "futex_wakeup_all: error in waking up threads" );
      return r;
  }
  
  } /* namespace internal */
  
  } /* namespace tbb */
  
  #endif /* SYS_futex */
  