lib/closeout.c

   1 /* closeout.c - close standard output
   2    Copyright (C) 1998, 1999 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program 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
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 #if HAVE_CONFIG_H
  19 # include <config.h>
  20 #endif
  21
  22 #if ENABLE_NLS
  23 # include <libintl.h>
  24 # define _(Text) gettext (Text)
  25 #else
  26 # define _(Text) Text
  27 #endif
  28
  29 #if HAVE_STDLIB_H
  30 # include <stdlib.h>
  31 #endif
  32 #ifndef EXIT_FAILURE
  33 # define EXIT_FAILURE 1
  34 #endif
  35
  36 #include <errno.h>
  37 #ifndef errno
  38 extern int errno;
  39 #endif
  40
  41 #include <stdio.h>
  42 #include "closeout.h"
  43 #include "error.h"
  44
  45 /* Close standard output, exiting with status STATUS on failure.
  46    If a program writes *anything* to stdout, that program should `fflush'
  47    stdout and make sure that it succeeds before exiting.  Otherwise,
  48    suppose that you go to the extreme of checking the return status
  49    of every function that does an explicit write to stdout.  The last
  50    printf can succeed in writing to the internal stream buffer, and yet
  51    the fclose(stdout) could still fail (due e.g., to a disk full error)
  52    when it tries to write out that buffered data.  Thus, you would be
  53    left with an incomplete output file and the offending program would
  54    exit successfully.
  55
  56    FIXME: note the fflush suggested above is implicit in the fclose
  57    we actually do below.  Consider doing only the fflush and/or using
  58    setvbuf to inhibit buffering.
  59
  60    Besides, it's wasteful to check the return value from every call
  61    that writes to stdout -- just let the internal stream state record
  62    the failure.  That's what the ferror test is checking below.
  63
  64    It's important to detect such failures and exit nonzero because many
  65    tools (most notably `make' and other build-management systems) depend
  66    on being able to detect failure in other tools via their exit status.  */
  67 void
  68 close_stdout_status (int status)
  69 {
  70   if (ferror (stdout))
  71     error (status, 0, _("write error"));
  72   if (fclose (stdout) != 0)
  73     error (status, errno, _("write error"));
  74 }
  75
  76 /* Close standard output, exiting with status EXIT_FAILURE on failure.  */
  77 void
  78 close_stdout (void)
  79 {
  80   close_stdout_status (EXIT_FAILURE);
  81 }