wait -n ignores invalid pids when valid pids are listed
Given a background process that has exited before the script got to wait -n:
function foo() { return 1; }
foo & FOO_PID=$!
function bar() { sleep 1; }
bar & BAR_PID=$!
sleep 0.1
# should exit with 127 since FOO_PID is non-existent now
wait -n $FOO_PID $BAR_PID
Then wait -n will wait on BAR_PID to exit, despite the fact that FOO_PID is
invalid. (Tested with 5.0.17.)
Shouldn't it immediately exit with 127, as the docs suggest, since one id
specifies a non-existent process?
The way it currently works makes it hard to make a script that waits for one
of a set of background processes to exit (ie. that fails if one of a set of
background processes fails), since any error that happens before the script
reaches the wait will simply be ignored.
Re: wait -n ignores invalid pids when valid pids are listed (solved!)
Am Dienstag, 27. April 2021, 11:45:44 CEST schrieb Robert Elz:
> Date:Tue, 27 Apr 2021 05:57:40 +
> From: "Beer, Mathis"
> Message-ID: <3024777.xmhlYjkYgV@ka-nl-mbeer>
>
> | Given a background process that has exited before the script got to wait
> | -n:
> |
> | function foo() { return 1; }
> | foo & FOO_PID=$!
> |
> | function bar() { sleep 1; }
> | bar & BAR_PID=$!
> |
> | sleep 0.1
> | # should exit with 127 since FOO_PID is non-existent now
> | wait -n $FOO_PID $BAR_PID
>
> That's not the way it works, pid's "exist" for these purposes until
> waited upon (just as they do in the process table for processes and
> the wait() sys call).
>
> The exit status should be 1, as that's the exit status of foo.
>
> | Then wait -n will wait on BAR_PID to exit, despite the fact that FOO_PID
> | is
> | invalid. (Tested with 5.0.17.)
>
> A second wait -n (in bash) generates a diagnostic about the pid that
> no longer exists (the NetBSD sh which has the same options doesn't do that)
> but waits for anything valid.
>
> | The way it currently works makes it hard to make a script that waits for
> | one of a set of background processes to exit
>
> Not if you code it properly. Use -p to help. It all just works.
>
> | (ie. that fails if one of a set of
> | background processes fails), since any error that happens before the
> | script
> | reaches the wait will simply be ignored.
>
> No, it won't.
>
> kre
Ah sorry, my first reply got lost cause I didn't do "reply to list" correctly.
Yes, wait -n does the right thing. I hadn't realized at the time that the
behavior in an interactive shell and a script was different, and all my tests
were done in an interactive shell.
All is good!
[PATCH] Add missing docs for 'set +o', 'set -o'
Add documentation for 'set -o', 'set +o' syntax to 'help set', 'info'.
'set -o'/'set +o' matches the POSIX behavior, but Bash's own documentation
should also mention it.
Phrasing is copied from the manpage, which already mentions it.
---
builtins/set.def | 4
doc/bashref.texi | 5 +
2 files changed, 9 insertions(+)
diff --git a/builtins/set.def b/builtins/set.def
index 44f17691..b922ca97 100644
--- a/builtins/set.def
+++ b/builtins/set.def
@@ -114,6 +114,10 @@ Options:
vi use a vi-style line editing interface
#endif /* READLINE */
xtrace same as -x
+ If -o is supplied with no option-name, the values of the
+ current options are printed. If +o is supplied with no
+ option-name, a series of set commands to recreate the current
+ option settings is displayed on the standard output.
-p Turned on whenever the real and effective user ids do not match.
Disables processing of the $ENV file and importing of shell
functions. Turning this option off causes the effective uid and
diff --git a/doc/bashref.texi b/doc/bashref.texi
index b0dc2fad..99c2875e 100644
--- a/doc/bashref.texi
+++ b/doc/bashref.texi
@@ -5401,6 +5401,11 @@ This also affects the editing interface used for
@code{read -e}.
Same as @code{-x}.
@end table
+If @code{-o} is supplied with no @var{option-name}, the values of the
+current options are printed. If @code{+o} is supplied with no
+@var{option-name}, a series of @code{set} commands to recreate the current
+option settings is displayed on the standard output.
+
@item -p
Turn on privileged mode.
In this mode, the @env{$BASH_ENV} and @env{$ENV} files are not
Re: [PATCH] Add missing docs for 'set +o', 'set -o'
On Tue, Jul 18, 2023, at 20:58:50 CEST, Lawrence Velázquez wrote: > Presumably the synopses in all locations should also use this: > > -o [option-name] > +o [option-name] > > -- > vq Far as I can tell, they all already have it. It's just at the very bottom of the 'set' option list, whereas the '+o'/'-o' docs are below the '-o' part.
