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glibc  2.9
errnobug.c
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00001 /* Regression test for reported old bug that errno is clobbered
00002    by the first successful output to a stream on an unseekable object.
00003    Copyright (C) 1995, 1997 Free Software Foundation, Inc.
00004    This file is part of the GNU C Library.
00005 
00006    The GNU C Library is free software; you can redistribute it and/or
00007    modify it under the terms of the GNU Lesser General Public
00008    License as published by the Free Software Foundation; either
00009    version 2.1 of the License, or (at your option) any later version.
00010 
00011    The GNU C Library is distributed in the hope that it will be useful,
00012    but WITHOUT ANY WARRANTY; without even the implied warranty of
00013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014    Lesser General Public License for more details.
00015 
00016    You should have received a copy of the GNU Lesser General Public
00017    License along with the GNU C Library; if not, write to the Free
00018    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00019    02111-1307 USA.  */
00020 
00021 #include <errno.h>
00022 #include <stdio.h>
00023 #include <unistd.h>
00024 
00025 int
00026 main (void)
00027 {
00028   int fd[2];
00029   FILE *f;
00030 
00031   /* Get a stream that cannot seek.  */
00032 
00033   if (pipe (fd))
00034     {
00035       perror ("pipe");
00036       return 1;
00037     }
00038   f = fdopen (fd[1], "w");
00039   if (f == NULL)
00040     {
00041       perror ("fdopen");
00042       return 1;
00043     }
00044 
00045   errno = 0;
00046   if (fputs ("fnord", f) == EOF)
00047     {
00048       perror ("fputs");
00049       return 1;
00050     }
00051 
00052   if (errno)
00053     {
00054       perror ("errno gratuitously set -- TEST FAILED");
00055       return 1;
00056     }
00057 
00058   puts ("Test succeeded.");
00059   return 0;
00060 }