/* Copyright (C) 2003, 2004, 2007 Free Software Foundation, Inc.   This file is part of the GNU C Library.   Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.   The GNU C Library is free software; you can redistribute it and/or   modify it under the terms of the GNU Lesser General Public   License as published by the Free Software Foundation; either   version 2.1 of the License, or (at your option) any later version.   The GNU C Library 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   Lesser General Public License for more details.   You should have received a copy of the GNU Lesser General Public   License along with the GNU C Library; if not, write to the Free   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA   02111-1307 USA.  */#include "pthreadP.h"#include <lowlevellock.h>unsigned long int __fork_generation attribute_hidden;static voidclear_once_control (void *arg){  pthread_once_t *once_control = (pthread_once_t *) arg;  *once_control = 0;  lll_futex_wake (once_control, INT_MAX, LLL_PRIVATE);}int__pthread_once (once_control, init_routine)     pthread_once_t *once_control;     void (*init_routine) (void);{  while (1)    {      int oldval, val, newval;      val = *once_control;      do	{	  /* Check if the initialized has already been done.  */	  if ((val & 2) != 0)	    return 0;	  oldval = val;	  newval = (oldval & 3) | __fork_generation | 1;	  val = atomic_compare_and_exchange_val_acq (once_control, newval,						     oldval);	}      while (__builtin_expect (val != oldval, 0));      /* Check if another thread already runs the initializer.	*/      if ((oldval & 1) != 0)	{	  /* Check whether the initializer execution was interrupted	     by a fork.	 */	  if (((oldval ^ newval) & -4) == 0)	    {	      /* Same generation, some other thread was faster. Wait.  */	      lll_futex_wait (once_control, newval, LLL_PRIVATE);	      continue;	    }	}      /* This thread is the first here.  Do the initialization.	 Register a cleanup handler so that in case the thread gets	 interrupted the initialization can be restarted.  */      pthread_cleanup_push (clear_once_control, once_control);      init_routine ();      pthread_cleanup_pop (0);      /* Add one to *once_control.  */      atomic_increment (once_control);      /* Wake up all other threads.  */      lll_futex_wake (once_control, INT_MAX, LLL_PRIVATE);      break;    }  return 0;}weak_alias (__pthread_once, pthread_once)strong_alias (__pthread_once, __pthread_once_internal)