Date: Mon, 27 Apr 2009 02:20:02 GMT From: Garrett Cooper <gcooper@FreeBSD.org> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/124748: [patch] sh(1): sh -c 'exit -1' fails with "Illegal number: -1", instead of exiting with a code of 255 Message-ID: <200904270220.n3R2K2p4049921@freefall.freebsd.org>
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The following reply was made to PR bin/124748; it has been noted by GNATS.
From: Garrett Cooper <gcooper@FreeBSD.org>
To: Jilles Tjoelker <jilles@stack.nl>
Cc: bug-followup@freebsd.org
Subject: Re: bin/124748: [patch] sh(1): sh -c 'exit -1' fails with "Illegal
number: -1", instead of exiting with a code of 255
Date: Sun, 26 Apr 2009 18:46:43 -0700
On Sun, Apr 26, 2009 at 7:40 AM, Jilles Tjoelker <jilles@stack.nl> wrote:
> Do people actually use 'exit -1' instead of the clearer 'exit 255'? '-1'
> is not an unsigned integer, so not a posix compliant parameter to the
> exit special builtin. Even then, sh still aborts a script with a nonzero
> exit code if exit is used wrongly like this.
Some people do, but I've since then stopped doing this.
The question I have is:
- Is the value of the return code uint8_t?
- Where in the documentation for sh(1) does it say that it can't be
<0? Here are all of the relevant documentation items for exit codes I
could find:
Command Exit Status
Each command has an exit status that can influence the behavior of other
shell commands. The paradigm is that a command exits with zero for nor-
mal or success, and non-zero for failure, error, or a false indication.
The man page for each command should indicate the various exit codes and
what they mean. Additionally, the built-in commands return exit codes,
as does an executed shell function.
If a command is terminated by a signal, its exit status is 128 plus the
signal number. Signal numbers are defined in the header file
<sys/signal.h>.
----
exit [exitstatus]
Terminate the shell process. If exitstatus is given it is used
as the exit status of the shell; otherwise the exit status of the
preceding command is used.
----
Nowhere in the above documentation does it mention valid limits being
in the set, [0, 128+SIGRTMAX] => [0, 254]. It's merely implied by the
resources at one's disposal (the source, sys/signal.h, etc).
Thanks,
-Garrett
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