GNU bug report logs - #34488
Add sort --limit, or document workarounds for sort|head error messages

Previous Next

Full log

View this message in rfc822 format

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Assaf Gordon <assafgordon <at> gmail.com>
Cc: Eric Blake <eblake <at> redhat.com>, Bernhard Voelker <mail <at> bernhard-voelker.de>, Pádraig Brady <P <at> draigBrady.com>, 34488 <at> debbugs.gnu.org, 積丹尼 Dan Jacobson <jidanni <at> jidanni.org>
Subject: bug#34488: Add sort --limit, or document workarounds for sort|head error messages
Date: Sun, 24 Feb 2019 10:33:47 -0800

Thanks for doing all that. Although Pádraig is not enthusiastic about a shortcut 
like -p, I'm a bit warmer to it, as it's an important special case to fix a wart 
in POSIX. No big deal either way.

The documentation should mention that SIGCHLD is special, in that 
--ignore-signal=CHLD might have no effect (POSIX says it's unspecified).

The documentation should say what happens if mutually-contradictory options are 
specified, e.g., '--default-signal=INT --ignore-signal=INT'. Presumably they are 
processed left-to-right, as is traditional for 'env' with contradictory operands.

There should be options --block-signal[=SIG], --unblock-signal[=SIG], and 
--setmask-signal[=SIG] that affect the signal mask, which is also inherited by 
the child. These can be implemented via pthread_sigmask.

The documentation should echo this suggestion in 
<http://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html>: "many 
existing applications wrongly assume that they start with certain signals set to 
the default action and/or unblocked.... Therefore, it is best not to block or 
ignore signals across execs without explicit reason to do so, and especially not 
to block signals across execs of arbitrary (not closely cooperating) programs."

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.