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/* closeout.c - close standard output
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Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004 Free Software
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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#define _(msgid) gettext (msgid)
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#include "__fpending.h"
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# include "unlocked-io.h"
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static const char *file_name;
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/* Set the file name to be reported in the event an error is detected
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close_stdout_set_file_name (const char *file)
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/* Close standard output, exiting with status 'exit_failure' on failure.
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If a program writes *anything* to stdout, that program should close
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stdout and make sure that it succeeds before exiting. Otherwise,
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suppose that you go to the extreme of checking the return status
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of every function that does an explicit write to stdout. The last
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printf can succeed in writing to the internal stream buffer, and yet
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the fclose(stdout) could still fail (due e.g., to a disk full error)
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when it tries to write out that buffered data. Thus, you would be
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left with an incomplete output file and the offending program would
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exit successfully. Even calling fflush is not always sufficient,
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since some file systems (NFS and CODA) buffer written/flushed data
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until an actual close call.
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Besides, it's wasteful to check the return value from every call
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that writes to stdout -- just let the internal stream state record
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the failure. That's what the ferror test is checking below.
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It's important to detect such failures and exit nonzero because many
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tools (most notably `make' and other build-management systems) depend
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on being able to detect failure in other tools via their exit status. */
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bool prev_fail = ferror (stdout);
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bool none_pending = (0 == __fpending (stdout));
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bool fclose_fail = fclose (stdout);
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if (prev_fail || fclose_fail)
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int e = fclose_fail ? errno : 0;
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char const *write_error;
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/* If ferror returned zero, no data remains to be flushed, and we'd
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otherwise fail with EBADF due to a failed fclose, then assume that
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it's ok to ignore the fclose failure. That can happen when a
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program like cp is invoked like this `cp a b >&-' (i.e., with
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stdout closed) and doesn't generate any output (hence no previous
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error and nothing to be flushed). */
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if (e == EBADF && !prev_fail && none_pending)
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write_error = _("write error");
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error (exit_failure, e, "%s: %s", quotearg_colon (file_name),
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error (exit_failure, e, "%s", write_error);
added
removed
gnulib/lib/closeout.c
