stdio-common/tst-put-error.c

   1 /* Verify that print functions return error when there is an I/O error.
   2
   3    Copyright (C) 2005-2024 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <errno.h>
  21 #include <error.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25
  26
  27 static int
  28 do_test (void)
  29 {
  30   char tmpl[] = "/tmp/tst-put-error.XXXXXX";
  31   int fd = mkstemp (tmpl);
  32   if (fd == -1)
  33     error (EXIT_FAILURE, errno, "cannot create temporary file");
  34   FILE *fp = fdopen (fd, "w");
  35   if (fp == NULL)
  36     error (EXIT_FAILURE, errno, "fdopen");
  37
  38   /* All of the tests below verify that flushing buffers result in failure of
  39      the fprintf calls.  We ensure that the buffer is flushed at the end of
  40      each fprintf call by doing two things - setting the file pointer to
  41      line-buffered so that it is flushed whenever it encounters a newline and
  42      then ensuring that there is a newline in each of the format strings we
  43      pass to fprintf.  */
  44
  45   setlinebuf (fp);
  46   close (fd);
  47   unlink (tmpl);
  48
  49   int n = fprintf (fp, "hello world\n");
  50   printf ("fprintf = %d\n", n);
  51   if (n >= 0)
  52     error (EXIT_FAILURE, 0, "first fprintf succeeded");
  53
  54   n = fprintf (fp, "hello world\n");
  55   printf ("fprintf = %d\n", n);
  56   if (n >= 0)
  57     error (EXIT_FAILURE, 0, "second fprintf succeeded");
  58
  59   /* Padded printing takes a different code path.  */
  60   n = fprintf (fp, "%100s\n", "foo");
  61   printf ("fprintf = %d\n", n);
  62   if (n >= 0)
  63     error (EXIT_FAILURE, 0, "padded fprintf succeeded");
  64
  65   return 0;
  66 }
  67
  68 #define TEST_FUNCTION do_test ()
  69 #include "../test-skeleton.c"