mq_notify.c

glibc 库, 不仅可以学习使用库函数,还可以学习函数的具体实现,是提高功力的好资料

/* Copyright (C) 2004, 2005 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   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 <errno.h>
#include <mqueue.h>
#include <stddef.h>
#include <sysdep.h>

#ifdef __NR_mq_notify

/* Register notification upon message arrival to an empty message queue
   MQDES.  */
int
mq_notify (mqd_t mqdes, const struct sigevent *notification)
{
  /* mq_notify which handles SIGEV_THREAD is included in the thread
     add-on.  */
  if (notification != NULL
      && notification->sigev_notify == SIGEV_THREAD)
    {
      __set_errno (ENOSYS);
      return -1;
    }
  return INLINE_SYSCALL (mq_notify, 2, mqdes, notification);
}

#else
# include <rt/mq_notify.c>
#endif