sysdeps/unix/sysv/linux/eventfd.c

   1 /* Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <sys/eventfd.h>
  21 #include <sysdep.h>
  22 #include <kernel-features.h>
  23
  24
  25 int
  26 eventfd (int count, int flags)
  27 {
  28 #ifdef __NR_eventfd2
  29   int res = INLINE_SYSCALL (eventfd2, 2, count, flags);
  30 # ifndef __ASSUME_EVENTFD2
  31   if (res != -1 || errno != ENOSYS)
  32 # endif
  33     return res;
  34 #endif
  35
  36 #ifndef __ASSUME_EVENTFD2
  37   /* The old system call has no flag parameter which is bad.  So we have
  38      to wait until we have to support to pass additional values to the
  39      kernel (sys_indirect) before implementing setting flags like
  40      O_NONBLOCK etc.  */
  41   if (flags != 0)
  42     {
  43       __set_errno (EINVAL);
  44       return -1;
  45     }
  46
  47 # ifdef __NR_eventfd
  48   return INLINE_SYSCALL (eventfd, 1, count);
  49 # else
  50   __set_errno (ENOSYS);
  51   return -1;
  52 # endif
  53 #elif !defined __NR_eventfd2
  54 # error "__ASSUME_EVENTFD2 defined but not __NR_eventfd2"
  55 #endif
  56 }