Mercurial > hg > octave-nkf > gnulib-hg
annotate lib/close-stream.c @ 9268:a553c18c572d
Rename sys_time_.h to sys_time.in.h.
| author | Bruno Haible <bruno@clisp.org> |
|---|---|
| date | Tue, 02 Oct 2007 00:37:40 +0200 |
| parents | cc316ffcb4fc |
| children | bbbbbf4cd1c5 |
| rev | line source |
|---|---|
| 7035 | 1 /* Close a stream, with nicer error checking than fclose's. |
| 2 | |
|
9183
cc316ffcb4fc
Rename __fpending.c -> fpending.c and __fpending.h -> fpending.h
Jim Meyering <jim@meyering.net>
parents:
7302
diff
changeset
|
3 Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2006, 2007 Free |
| 7035 | 4 Software Foundation, Inc. |
| 5 | |
| 6 This program is free software; you can redistribute it and/or modify | |
| 7 it under the terms of the GNU General Public License as published by | |
| 8 the Free Software Foundation; either version 2, or (at your option) | |
| 9 any later version. | |
| 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 | |
| 17 along with this program; if not, write to the Free Software Foundation, | |
| 18 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ | |
| 19 | |
|
7302
8a1a9361108c
* _fpending.c: Include <config.h> unconditionally, since we no
Paul Eggert <eggert@cs.ucla.edu>
parents:
7035
diff
changeset
|
20 #include <config.h> |
| 7035 | 21 |
| 22 #include "close-stream.h" | |
| 23 | |
| 24 #include <errno.h> | |
| 25 #include <stdbool.h> | |
| 26 | |
|
9183
cc316ffcb4fc
Rename __fpending.c -> fpending.c and __fpending.h -> fpending.h
Jim Meyering <jim@meyering.net>
parents:
7302
diff
changeset
|
27 #include "fpending.h" |
| 7035 | 28 |
| 29 #if USE_UNLOCKED_IO | |
| 30 # include "unlocked-io.h" | |
| 31 #endif | |
| 32 | |
| 33 /* Close STREAM. Return 0 if successful, EOF (setting errno) | |
| 34 otherwise. A failure might set errno to 0 if the error number | |
| 35 cannot be determined. | |
| 36 | |
| 37 If a program writes *anything* to STREAM, that program should close | |
| 38 STREAM and make sure that it succeeds before exiting. Otherwise, | |
| 39 suppose that you go to the extreme of checking the return status | |
| 40 of every function that does an explicit write to STREAM. The last | |
| 41 printf can succeed in writing to the internal stream buffer, and yet | |
| 42 the fclose(STREAM) could still fail (due e.g., to a disk full error) | |
| 43 when it tries to write out that buffered data. Thus, you would be | |
| 44 left with an incomplete output file and the offending program would | |
| 45 exit successfully. Even calling fflush is not always sufficient, | |
| 46 since some file systems (NFS and CODA) buffer written/flushed data | |
| 47 until an actual close call. | |
| 48 | |
| 49 Besides, it's wasteful to check the return value from every call | |
| 50 that writes to STREAM -- just let the internal stream state record | |
| 51 the failure. That's what the ferror test is checking below. */ | |
| 52 | |
| 53 int | |
| 54 close_stream (FILE *stream) | |
| 55 { | |
| 56 bool some_pending = (__fpending (stream) != 0); | |
| 57 bool prev_fail = (ferror (stream) != 0); | |
| 58 bool fclose_fail = (fclose (stream) != 0); | |
| 59 | |
| 60 /* Return an error indication if there was a previous failure or if | |
| 61 fclose failed, with one exception: ignore an fclose failure if | |
| 62 there was no previous error, no data remains to be flushed, and | |
| 63 fclose failed with EBADF. That can happen when a program like cp | |
| 64 is invoked like this `cp a b >&-' (i.e., with standard output | |
| 65 closed) and doesn't generate any output (hence no previous error | |
| 66 and nothing to be flushed). */ | |
| 67 | |
| 68 if (prev_fail || (fclose_fail && (some_pending || errno != EBADF))) | |
| 69 { | |
| 70 if (! fclose_fail) | |
| 71 errno = 0; | |
| 72 return EOF; | |
| 73 } | |
| 74 | |
| 75 return 0; | |
| 76 } |