1 files changed, 101 insertions, 0 deletions
diff --git a/lib/closeout.c b/lib/closeout.c
new file mode 100644
index 0000000..5d0509d
--- /dev/null
+++ b/lib/closeout.c
@@ -0,0 +1,101 @@
+/* closeout.c - close standard output
+
+   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004 Free Software
+   Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "closeout.h"
+
+#include <stdio.h>
+#include <stdbool.h>
+#include <errno.h>
+
+#include "gettext.h"
+#define _(msgid) gettext (msgid)
+
+#include "error.h"
+#include "exitfail.h"
+#include "quotearg.h"
+#include "__fpending.h"
+
+#if USE_UNLOCKED_IO
+# include "unlocked-io.h"
+#endif
+
+static const char *file_name;
+
+/* Set the file name to be reported in the event an error is detected
+   by close_stdout.  */
+void
+close_stdout_set_file_name (const char *file)
+{
+  file_name = file;
+}
+
+/* Close standard output, exiting with status 'exit_failure' on failure.
+   If a program writes *anything* to stdout, that program should close
+   stdout and make sure that it succeeds before exiting.  Otherwise,
+   suppose that you go to the extreme of checking the return status
+   of every function that does an explicit write to stdout.  The last
+   printf can succeed in writing to the internal stream buffer, and yet
+   the fclose(stdout) could still fail (due e.g., to a disk full error)
+   when it tries to write out that buffered data.  Thus, you would be
+   left with an incomplete output file and the offending program would
+   exit successfully.  Even calling fflush is not always sufficient,
+   since some file systems (NFS and CODA) buffer written/flushed data
+   until an actual close call.
+
+   Besides, it's wasteful to check the return value from every call
+   that writes to stdout -- just let the internal stream state record
+   the failure.  That's what the ferror test is checking below.
+
+   It's important to detect such failures and exit nonzero because many
+   tools (most notably `make' and other build-management systems) depend
+   on being able to detect failure in other tools via their exit status.  */
+
+void
+close_stdout (void)
+{
+  bool prev_fail = ferror (stdout);
+  bool none_pending = (0 == __fpending (stdout));
+  bool fclose_fail = fclose (stdout);
+
+  if (prev_fail || fclose_fail)
+    {
+      int e = fclose_fail ? errno : 0;
+      char const *write_error;
+
+      /* If ferror returned zero, no data remains to be flushed, and we'd
+	 otherwise fail with EBADF due to a failed fclose, then assume that
+	 it's ok to ignore the fclose failure.  That can happen when a
+	 program like cp is invoked like this `cp a b >&-' (i.e., with
+	 stdout closed) and doesn't generate any output (hence no previous
+	 error and nothing to be flushed).  */
+      if (e == EBADF && !prev_fail && none_pending)
+	return;
+
+      write_error = _("write error");
+      if (file_name)
+	error (exit_failure, e, "%s: %s", quotearg_colon (file_name),
+	       write_error);
+      else
+	error (exit_failure, e, "%s", write_error);
+    }
+}