From 710fe413fed61aacad4e0124eb7fcebc3a20fb6c Mon Sep 17 00:00:00 2001 From: Pádraig Brady Date: Tue, 20 Oct 2009 19:19:58 +0100 Subject: md5sum, sha*sum, sum: line-buffer the printed checksums * src/md5sum.c (main): Set stdout to line buffered mode to ensure parallel running instances don't intersperse their output. This adds 5% to the run time in the worst case of many zero length files, or 2% with standard file sizes. * src/sum.c (main): Likewise. * tests/misc/md5sum-parallel: New test for atomic output. * tests/Makefile.am: Reference it. * NEWS: Mention the fix --- src/md5sum.c | 6 ++++-- src/sum.c | 4 ++++ 2 files changed, 8 insertions(+), 2 deletions(-) (limited to 'src') diff --git a/src/md5sum.c b/src/md5sum.c index aa2a144a7..b7db03ecd 100644 --- a/src/md5sum.c +++ b/src/md5sum.c @@ -513,7 +513,6 @@ digest_check (const char *checkfile_name) if (!status_only) { printf (_("%s: FAILED open or read\n"), filename); - fflush (stdout); } } else @@ -539,7 +538,6 @@ digest_check (const char *checkfile_name) printf ("%s: %s\n", filename, _("FAILED")); else if (!quiet) printf ("%s: %s\n", filename, _("OK")); - fflush (stdout); } } } @@ -619,6 +617,10 @@ main (int argc, char **argv) atexit (close_stdout); + /* Line buffer stdout to ensure lines are written atomically and immediately + so that processes running in parallel do not intersperse their output. */ + setvbuf (stdout, NULL, _IOLBF, 0); + while ((opt = getopt_long (argc, argv, "bctw", long_options, NULL)) != -1) switch (opt) { diff --git a/src/sum.c b/src/sum.c index 91d7f34ba..f0e0cc09a 100644 --- a/src/sum.c +++ b/src/sum.c @@ -233,6 +233,10 @@ main (int argc, char **argv) atexit (close_stdout); + /* Line buffer stdout to ensure lines are written atomically and immediately + so that processes running in parallel do not intersperse their output. */ + setvbuf (stdout, NULL, _IOLBF, 0); + have_read_stdin = false; while ((optc = getopt_long (argc, argv, "rs", longopts, NULL)) != -1) -- cgit v1.2.3-70-g09d2