1
/* Close standard input, rewinding seekable stdin if necessary.
3
Copyright (C) 2007 Free Software Foundation, Inc.
5
This program is free software; you can redistribute it and/or modify
6
it under the terms of the GNU General Public License as published by
7
the Free Software Foundation; either version 2, or (at your option)
10
This program is distributed in the hope that it will be useful,
11
but WITHOUT ANY WARRANTY; without even the implied warranty of
12
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13
GNU General Public License for more details.
15
You should have received a copy of the GNU General Public License
16
along with this program; if not, write to the Free Software Foundation,
17
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
29
#define _(msgid) gettext (msgid)
31
#include "close-stream.h"
37
static const char *file_name;
39
/* Set the file name to be reported in the event an error is detected
40
on stdin by close_stdin. See also close_stdout_set_file_name, if
41
an error is detected when closing stdout. */
43
close_stdin_set_file_name (const char *file)
48
/* Close standard input, rewinding any unused input if stdin is
49
seekable. On error, issue a diagnostic and _exit with status
50
'exit_failure'. Then call close_stdout.
52
Most programs can get by with close_stdout. close_stdin is only
53
needed when a program wants to guarantee that partially read input
54
from seekable stdin is not consumed, for any subsequent clients.
55
For example, POSIX requires that these two commands behave alike:
57
(sed -ne 1q; cat) < file
60
Since close_stdin is commonly registered via 'atexit', POSIX
61
and the C standard both say that it should not call 'exit',
62
because the behavior is undefined if 'exit' is called more than
63
once. So it calls '_exit' instead of 'exit'. If close_stdin
64
is registered via atexit before other functions are registered,
65
the other functions can act before this _exit is invoked.
67
Applications that use close_stdout should flush any streams other
68
than stdin, stdout, and stderr before exiting, since the call to
69
_exit will bypass other buffer flushing. Applications should be
70
flushing and closing other streams anyway, to check for I/O errors.
71
Also, applications should not use tmpfile, since _exit can bypass
72
the removal of these files.
74
It's important to detect such failures and exit nonzero because many
75
tools (most notably `make' and other build-management systems) depend
76
on being able to detect failure in other tools via their exit status. */
83
/* Only attempt flush if stdin is seekable, as fflush is entitled to
84
fail on non-seekable streams. */
85
if (fseeko (stdin, 0, SEEK_CUR) == 0 && fflush (stdin) != 0)
87
if (close_stream (stdin) != 0)
91
/* Report failure, but defer exit until after closing stdout,
92
since the failure report should still be flushed. */
93
char const *close_error = _("error closing file");
95
error (0, errno, "%s: %s", quotearg_colon (file_name),
98
error (0, errno, "%s", close_error);
104
_exit (exit_failure);