lib/closeout.c

   1 /* closeout.c - close standard output
   2    Copyright (C) 1998, 1999, 2000 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 <stdio.h>
  37
  38 #include <errno.h>
  39 #ifndef errno
  40 extern int errno;
  41 #endif
  42
  43 #include "closeout.h"
  44 #include "error.h"
  45 #include "quotearg.h"
  46
  47 static int default_exit_status = EXIT_FAILURE;
  48 static const char *file_name;
  49
  50 /* Set the value to be used for the exit status when close_stdout is called.
  51    This is useful when it is not convenient to call close_stdout_status,
  52    e.g., when close_stdout is called via atexit.  */
  53 void
  54 close_stdout_set_status (int status)
  55 {
  56   default_exit_status = status;
  57 }
  58
  59 /* Set the file name to be reported in the event an error is detected
  60    by close_stdout_status.  */
  61 void
  62 close_stdout_set_file_name (const char *file)
  63 {
  64   file_name = file;
  65 }
  66
  67 /* Close standard output, exiting with status STATUS on failure.
  68    If a program writes *anything* to stdout, that program should `fflush'
  69    stdout and make sure that it succeeds before exiting.  Otherwise,
  70    suppose that you go to the extreme of checking the return status
  71    of every function that does an explicit write to stdout.  The last
  72    printf can succeed in writing to the internal stream buffer, and yet
  73    the fclose(stdout) could still fail (due e.g., to a disk full error)
  74    when it tries to write out that buffered data.  Thus, you would be
  75    left with an incomplete output file and the offending program would
  76    exit successfully.
  77
  78    FIXME: note the fflush suggested above is implicit in the fclose
  79    we actually do below.  Consider doing only the fflush and/or using
  80    setvbuf to inhibit buffering.
  81
  82    Besides, it's wasteful to check the return value from every call
  83    that writes to stdout -- just let the internal stream state record
  84    the failure.  That's what the ferror test is checking below.
  85
  86    It's important to detect such failures and exit nonzero because many
  87    tools (most notably `make' and other build-management systems) depend
  88    on being able to detect failure in other tools via their exit status.  */
  89 void
  90 close_stdout_status (int status)
  91 {
  92   int e = ferror (stdout) ? 0 : -1;
  93
  94   if (fclose (stdout) != 0)
  95     e = errno;
  96
  97   if (0 <= e)
  98     {
  99       char const *write_error = _("write error");
 100       if (file_name)
 101         error (status, e, "%s: %s", quotearg_colon (file_name), write_error);
 102       else
 103         error (status, e, "%s", write_error);
 104     }
 105 }
 106
 107 /* Close standard output, exiting with status EXIT_FAILURE on failure.  */
 108 void
 109 close_stdout (void)
 110 {
 111   close_stdout_status (default_exit_status);
 112 }