sysdeps/unix/sysv/linux/wordsize-64/preadv.c

   1 /* 64-bit preadv.
   2    Copyright (C) 2012-2016 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <stddef.h>
  21 #include <sys/param.h>
  22 /* Hide the preadv64 declaration.  */
  23 #define preadv64 __redirect_preadv64
  24 #include <sys/uio.h>
  25
  26 #include <sysdep-cancel.h>
  27 #include <sys/syscall.h>
  28 #include <kernel-features.h>
  29
  30 #ifndef __ASSUME_PREADV
  31 static ssize_t __atomic_preadv_replacement (int, const struct iovec *,
  32                                             int, off_t) internal_function;
  33 #endif
  34
  35 ssize_t
  36 preadv (int fd, const struct iovec *vector, int count, off_t offset)
  37 {
  38 #ifdef __NR_preadv
  39   ssize_t result;
  40
  41   result = SYSCALL_CANCEL (preadv, fd, vector, count, offset);
  42 # ifdef __ASSUME_PREADV
  43   return result;
  44 # endif
  45 #endif
  46
  47 #ifndef __ASSUME_PREADV
  48 # ifdef __NR_preadv
  49   if (result >= 0 || errno != ENOSYS)
  50     return result;
  51 # endif
  52
  53   return __atomic_preadv_replacement (fd, vector, count, offset);
  54 #endif
  55 }
  56 #undef preadv64
  57 strong_alias (preadv, preadv64)
  58
  59 #ifndef __ASSUME_PREADV
  60 # define PREADV static internal_function __atomic_preadv_replacement
  61 # define PREAD __pread
  62 # define OFF_T off_t
  63 # include <sysdeps/posix/preadv.c>
  64 #endif