Mercurial > hg > octave-kai > gnulib-hg
annotate lib/close-stream.c @ 10622:ac6f431cc95d
New module 'fclose'.
| author | Bruno Haible <bruno@clisp.org> |
|---|---|
| date | Sat, 11 Oct 2008 14:18:29 +0200 |
| parents | 37b949ffd096 |
| children | e8d2c6fc33ad |
| rev | line source |
|---|---|
| 7035 | 1 /* Close a stream, with nicer error checking than fclose's. |
| 2 | |
|
10595
37b949ffd096
Add an option for ignoring EPIPE during close_stdout.
Bruno Haible <bruno@clisp.org>
parents:
9309
diff
changeset
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3 Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2006, 2007, 2008 Free |
| 7035 | 4 Software Foundation, Inc. |
| 5 | |
|
9309
bbbbbf4cd1c5
Change copyright notice from GPLv2+ to GPLv3+.
Bruno Haible <bruno@clisp.org>
parents:
9183
diff
changeset
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6 This program is free software: you can redistribute it and/or modify |
| 7035 | 7 it under the terms of the GNU General Public License as published by |
|
9309
bbbbbf4cd1c5
Change copyright notice from GPLv2+ to GPLv3+.
Bruno Haible <bruno@clisp.org>
parents:
9183
diff
changeset
|
8 the Free Software Foundation; either version 3 of the License, or |
|
bbbbbf4cd1c5
Change copyright notice from GPLv2+ to GPLv3+.
Bruno Haible <bruno@clisp.org>
parents:
9183
diff
changeset
|
9 (at your option) any later version. |
| 7035 | 10 |
| 11 This program is distributed in the hope that it will be useful, | |
| 12 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 14 GNU General Public License for more details. | |
| 15 | |
| 16 You should have received a copy of the GNU General Public License | |
|
9309
bbbbbf4cd1c5
Change copyright notice from GPLv2+ to GPLv3+.
Bruno Haible <bruno@clisp.org>
parents:
9183
diff
changeset
|
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 7035 | 18 |
|
7302
8a1a9361108c
* _fpending.c: Include <config.h> unconditionally, since we no
Paul Eggert <eggert@cs.ucla.edu>
parents:
7035
diff
changeset
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19 #include <config.h> |
| 7035 | 20 |
| 21 #include "close-stream.h" | |
| 22 | |
| 23 #include <errno.h> | |
| 24 #include <stdbool.h> | |
| 25 | |
|
9183
cc316ffcb4fc
Rename __fpending.c -> fpending.c and __fpending.h -> fpending.h
Jim Meyering <jim@meyering.net>
parents:
7302
diff
changeset
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26 #include "fpending.h" |
| 7035 | 27 |
| 28 #if USE_UNLOCKED_IO | |
| 29 # include "unlocked-io.h" | |
| 30 #endif | |
| 31 | |
| 32 /* Close STREAM. Return 0 if successful, EOF (setting errno) | |
| 33 otherwise. A failure might set errno to 0 if the error number | |
| 34 cannot be determined. | |
| 35 | |
|
10595
37b949ffd096
Add an option for ignoring EPIPE during close_stdout.
Bruno Haible <bruno@clisp.org>
parents:
9309
diff
changeset
|
36 A failure with errno set to EPIPE may or may not indicate an error |
|
37b949ffd096
Add an option for ignoring EPIPE during close_stdout.
Bruno Haible <bruno@clisp.org>
parents:
9309
diff
changeset
|
37 situation worth signaling to the user. See the documentation of the |
|
37b949ffd096
Add an option for ignoring EPIPE during close_stdout.
Bruno Haible <bruno@clisp.org>
parents:
9309
diff
changeset
|
38 close_stdout_set_ignore_EPIPE function for details. |
|
37b949ffd096
Add an option for ignoring EPIPE during close_stdout.
Bruno Haible <bruno@clisp.org>
parents:
9309
diff
changeset
|
39 |
| 7035 | 40 If a program writes *anything* to STREAM, that program should close |
| 41 STREAM and make sure that it succeeds before exiting. Otherwise, | |
| 42 suppose that you go to the extreme of checking the return status | |
| 43 of every function that does an explicit write to STREAM. The last | |
| 44 printf can succeed in writing to the internal stream buffer, and yet | |
| 45 the fclose(STREAM) could still fail (due e.g., to a disk full error) | |
| 46 when it tries to write out that buffered data. Thus, you would be | |
| 47 left with an incomplete output file and the offending program would | |
| 48 exit successfully. Even calling fflush is not always sufficient, | |
| 49 since some file systems (NFS and CODA) buffer written/flushed data | |
| 50 until an actual close call. | |
| 51 | |
| 52 Besides, it's wasteful to check the return value from every call | |
| 53 that writes to STREAM -- just let the internal stream state record | |
| 54 the failure. That's what the ferror test is checking below. */ | |
| 55 | |
| 56 int | |
| 57 close_stream (FILE *stream) | |
| 58 { | |
| 59 bool some_pending = (__fpending (stream) != 0); | |
| 60 bool prev_fail = (ferror (stream) != 0); | |
| 61 bool fclose_fail = (fclose (stream) != 0); | |
| 62 | |
| 63 /* Return an error indication if there was a previous failure or if | |
| 64 fclose failed, with one exception: ignore an fclose failure if | |
| 65 there was no previous error, no data remains to be flushed, and | |
| 66 fclose failed with EBADF. That can happen when a program like cp | |
| 67 is invoked like this `cp a b >&-' (i.e., with standard output | |
| 68 closed) and doesn't generate any output (hence no previous error | |
| 69 and nothing to be flushed). */ | |
| 70 | |
| 71 if (prev_fail || (fclose_fail && (some_pending || errno != EBADF))) | |
| 72 { | |
| 73 if (! fclose_fail) | |
| 74 errno = 0; | |
| 75 return EOF; | |
| 76 } | |
| 77 | |
| 78 return 0; | |
| 79 } |