Back to index

glibc  2.9
pipe.c
Go to the documentation of this file.
00001 /* Copyright (C) 1992,93,94,95,96,99,2000,2002 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <errno.h>
00020 #include <sys/socket.h>
00021 #include <sys/stat.h>
00022 #include <unistd.h>
00023 
00024 /* Create a one-way communication channel (pipe).
00025    Actually the channel is two-way on the Hurd.
00026    If successful, two file descriptors are stored in FDS;
00027    bytes written on FDS[1] can be read from FDS[0].
00028    Returns 0 if successful, -1 if not.  */
00029 int
00030 __pipe (int fds[2])
00031 {
00032   int save_errno = errno;
00033   int result;
00034 
00035   /* The magic S_IFIFO protocol tells the pflocal server to create
00036      sockets which report themselves as FIFOs, as POSIX requires for
00037      pipes.  */
00038   result = __socketpair (PF_LOCAL, SOCK_STREAM, S_IFIFO, fds);
00039   if (result == -1 && errno == EPROTONOSUPPORT)
00040     {
00041       /* We contacted an "old" pflocal server that doesn't support the
00042          magic S_IFIFO protocol.
00043         FIXME: Remove this junk somewhere in the future.  */
00044       __set_errno (save_errno);
00045       return __socketpair (PF_LOCAL, SOCK_STREAM, 0, fds);
00046     }
00047 
00048   return result;
00049 }
00050 libc_hidden_def (__pipe)
00051 weak_alias (__pipe, pipe)