sysdeps/unix/sysv/linux/bits/uio.h

   1 /* Copyright (C) 1996-2014 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #if !defined _SYS_UIO_H && !defined _FCNTL_H
  19 # error "Never include <bits/uio.h> directly; use <sys/uio.h> instead."
  20 #endif
  21
  22 #ifndef _BITS_UIO_H
  23 #define _BITS_UIO_H     1
  24
  25 #include <sys/types.h>
  26
  27
  28 /* We should normally use the Linux kernel header file to define this
  29    type and macros but this calls for trouble because of the header
  30    includes other kernel headers.  */
  31
  32 /* Size of object which can be written atomically.
  33
  34    This macro has different values in different kernel versions.  The
  35    latest versions of the kernel use 1024 and this is good choice.  Since
  36    the C library implementation of readv/writev is able to emulate the
  37    functionality even if the currently running kernel does not support
  38    this large value the readv/writev call will not fail because of this.  */
  39 #define UIO_MAXIOV      1024
  40
  41
  42 /* Structure for scatter/gather I/O.  */
  43 struct iovec
  44   {
  45     void *iov_base;     /* Pointer to data.  */
  46     size_t iov_len;     /* Length of data.  */
  47   };
  48
  49 #endif
  50
  51
  52 #ifdef __USE_GNU
  53 # if defined _SYS_UIO_H && !defined _BITS_UIO_H_FOR_SYS_UIO_H
  54 #  define _BITS_UIO_H_FOR_SYS_UIO_H 1
  55
  56 __BEGIN_DECLS
  57
  58 /* Read from another process' address space.  */
  59 extern ssize_t process_vm_readv (pid_t __pid, const struct iovec *__lvec,
  60                                  unsigned long int __liovcnt,
  61                                  const struct iovec *__rvec,
  62                                  unsigned long int __riovcnt,
  63                                  unsigned long int __flags)
  64   __THROW;
  65
  66 /* Write to another process' address space.  */
  67 extern ssize_t process_vm_writev (pid_t __pid, const struct iovec *__lvec,
  68                                   unsigned long int __liovcnt,
  69                                   const struct iovec *__rvec,
  70                                   unsigned long int __riovcnt,
  71                                   unsigned long int __flags)
  72   __THROW;
  73
  74 __END_DECLS
  75
  76 # endif
  77 #endif