From cd6cd3bd41bf69ca65c62a2f96de0ed89cb3c16e Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Sat, 22 Jul 2006 22:13:57 +0000 Subject: [PATCH] * modules/close-stream: New file. * modules/closeout (Description): Make it clear that it exits with a diagnostic on error. (Depends-on): Add close-stream. Remove fpending, stdbool. * MODULES.html.sh (File stream based Input/Output): Add close-stream. * lib/close-stream.c, lib/close-stream.h: New files. * m4/close-stream.m4: New file. --- ChangeLog | 8 +++++++ MODULES.html.sh | 1 + lib/ChangeLog | 4 ++++ lib/closeout.c | 70 +++++++++++++++++++++----------------------------------- m4/ChangeLog | 4 ++++ modules/closeout | 5 ++-- 6 files changed, 45 insertions(+), 47 deletions(-) diff --git a/ChangeLog b/ChangeLog index 3c70a356a..e08810959 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2006-07-22 Paul Eggert + + * modules/close-stream: New file. + * modules/closeout (Description): Make it clear that it exits + with a diagnostic on error. + (Depends-on): Add close-stream. Remove fpending, stdbool. + * MODULES.html.sh (File stream based Input/Output): Add close-stream. + 2006-05-01 Bruno Haible * build-aux/javacomp.sh.in: Update for changed javacomp.m4. diff --git a/MODULES.html.sh b/MODULES.html.sh index 125a009c4..56f26c4cb 100755 --- a/MODULES.html.sh +++ b/MODULES.html.sh @@ -1932,6 +1932,7 @@ func_all_modules () func_begin_table func_module fpending func_module closeout + func_module close-stream func_module stdio-safer func_module stdlib-safer func_module getpass diff --git a/lib/ChangeLog b/lib/ChangeLog index 006ac240e..c44cad7a0 100644 --- a/lib/ChangeLog +++ b/lib/ChangeLog @@ -1,3 +1,7 @@ +2006-07-22 Paul Eggert + + * close-stream.c, close-stream.h: New files. + 2005-07-05 Bruno Haible * printf-args.c (printf_fetchargs): Work around broken definition of diff --git a/lib/closeout.c b/lib/closeout.c index 2137fd4a3..f298d4bed 100644 --- a/lib/closeout.c +++ b/lib/closeout.c @@ -1,4 +1,4 @@ -/* closeout.c - close standard output +/* Close standard output, exiting with a diagnostic on error. Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2006 Free Software Foundation, Inc. @@ -23,21 +23,17 @@ #include "closeout.h" -#include -#include #include +#include +#include #include "gettext.h" #define _(msgid) gettext (msgid) +#include "close-stream.h" #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; @@ -49,22 +45,22 @@ 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. +/* Close standard output. On error, issue a diagnostic and _exit + with status 'exit_failure'. + + Since close_stdout is commonly registered via 'atexit', POSIX + and the C standard both say that it should not call 'exit', + because the behavior is undefined if 'exit' is called more than + once. So it calls '_exit' instead of 'exit'. If close_stdout + is registered via atexit before other functions are registered, + the other functions can act before this _exit is invoked. + + Applications that use close_stdout should flush any streams + other than stdout and stderr before exiting, since the call to + _exit will bypass other buffer flushing. Applications should + be flushing and closing other streams anyway, to check for I/O + errors. Also, applications should not use tmpfile, since _exit + can bypass the removal of these files. It's important to detect such failures and exit nonzero because many tools (most notably `make' and other build-management systems) depend @@ -73,29 +69,15 @@ close_stdout_set_file_name (const char *file) void close_stdout (void) { - bool none_pending = (__fpending (stdout) == 0); - bool prev_fail = (ferror (stdout) != 0); - bool fclose_fail = (fclose (stdout) != 0); - - if (prev_fail || fclose_fail) + if (close_stream (stdout) != 0) { - 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"); + char const *write_error = _("write error"); if (file_name) - error (exit_failure, e, "%s: %s", quotearg_colon (file_name), + error (0, errno, "%s: %s", quotearg_colon (file_name), write_error); else - error (exit_failure, e, "%s", write_error); + error (0, errno, "%s", write_error); + + _exit (exit_failure); } } diff --git a/m4/ChangeLog b/m4/ChangeLog index 3103ff2da..807e8c583 100644 --- a/m4/ChangeLog +++ b/m4/ChangeLog @@ -1,3 +1,7 @@ +2006-07-22 Paul Eggert + + * close-stream.m4: New file. + 2006-03-25 Bruno Haible * lib-link.m4 (AC_LIB_LINKFLAGS_FROM_LIBS): New macro. diff --git a/modules/closeout b/modules/closeout index e7c7416de..22d935ac5 100644 --- a/modules/closeout +++ b/modules/closeout @@ -1,5 +1,5 @@ Description: -Close stdout, checking for errors. +Close standard output, exiting with a diagnostic on error. Files: lib/closeout.h @@ -7,12 +7,11 @@ lib/closeout.c m4/closeout.m4 Depends-on: +close-stream gettext-h error quotearg -fpending exitfail -stdbool configure.ac: gl_CLOSEOUT -- 2.11.0