text: /*
   * libusbx synchronization using POSIX Threads
   *
   * Copyright © 2011 Vitali Lovich <vlovich@aliph.com>
   * Copyright © 2011 Peter Stuge <peter@stuge.se>
   *
   * This 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.
   *
   * This 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 this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #if defined(__linux__) || defined(__OpenBSD__)
  # include <unistd.h>
  # include <sys/syscall.h>
  #elif defined(__APPLE__)
  # include <mach/mach.h>
  #elif defined(__CYGWIN__)
  # include <windows.h>
  #endif
  
  #include "threads_posix.h"
  
  int usbi_mutex_init_recursive(pthread_mutex_t *mutex, pthread_mutexattr_t *attr)
  {
  	int err;
  	pthread_mutexattr_t stack_attr;
  	if (!attr) {
  		attr = &stack_attr;
  		err = pthread_mutexattr_init(&stack_attr);
  		if (err != 0)
  			return err;
  	}
  
  	/* mutexattr_settype requires _GNU_SOURCE or _XOPEN_SOURCE >= 500 on Linux */
  	err = pthread_mutexattr_settype(attr, PTHREAD_MUTEX_RECURSIVE);
  	if (err != 0)
  		goto finish;
  
  	err = pthread_mutex_init(mutex, attr);
  
  finish:
  	if (attr == &stack_attr)
  		pthread_mutexattr_destroy(&stack_attr);
  
  	return err;
  }
  
  int usbi_get_tid(void)
  {
  	int ret = -1;
  #if defined(__ANDROID__)
  	ret = gettid();
  #elif defined(__linux__)
  	ret = syscall(SYS_gettid);
  #elif defined(__OpenBSD__)
  	/* The following only works with OpenBSD > 5.1 as it requires
  	   real thread support. For 5.1 and earlier, -1 is returned. */
  	ret = syscall(SYS_getthrid);
  #elif defined(__APPLE__)
  	ret = mach_thread_self();
  	mach_port_deallocate(mach_task_self(), ret);
  #elif defined(__CYGWIN__)
  	ret = GetCurrentThreadId();
  #endif
  /* TODO: NetBSD thread ID support */
  	return ret;
  }
  