lib/read.c

   1 /* POSIX compatible read() function.
   2    Copyright (C) 2008-2011 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2011.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 /* Specification.  */
  21 #include <unistd.h>
  22
  23 /* Replace this function only if module 'nonblocking' is requested.  */
  24 #if GNULIB_NONBLOCKING
  25
  26 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
  27
  28 #  include <errno.h>
  29 #  include <io.h>
  30
  31 #  define WIN32_LEAN_AND_MEAN  /* avoid including junk */
  32 #  include <windows.h>
  33
  34 ssize_t
  35 rpl_read (int fd, void *buf, size_t count)
  36 #undef read
  37 {
  38   ssize_t ret = read (fd, buf, count);
  39
  40   if (ret < 0
  41       && GetLastError () == ERROR_NO_DATA)
  42     {
  43       HANDLE h = (HANDLE) _get_osfhandle (fd);
  44       if (GetFileType (h) == FILE_TYPE_PIPE)
  45         {
  46           /* h is a pipe or socket.  */
  47           DWORD state;
  48           if (GetNamedPipeHandleState (h, &state, NULL, NULL, NULL, NULL, 0)
  49               && (state & PIPE_NOWAIT) != 0)
  50             /* h is a pipe in non-blocking mode.
  51                Change errno from EINVAL to EAGAIN.  */
  52             errno = EAGAIN;
  53         }
  54     }
  55   return ret;
  56 }
  57
  58 # endif
  59 #endif