If I add a command after the builtin sleep, then the EXIT trap will be
triggered upon typing ctrl-C.
If the last command is removed, then the EXIT trap will not be
triggered upon typing ctrl-C.
Is this a bug in the built-in sleep? I am trying to inspect the C code
of sleep builtin, but it is very simple. I am not sure where the
problem comes from.
Could anybody take a look? Thanks.
$ cat main_INT.sh
#!/usr/bin/env bash
# vim: set noexpandtab tabstop=2:
source ../../../trapexit.sh
(
trapexit -q <<-'EOF'
echo Hello World!
EOF
source enable.sh
enable sleep
sleep 10
echo "$?"
)
$ ./main_INT.sh
^CHello World!
$ cat main_INT.sh
#!/usr/bin/env bash
# vim: set noexpandtab tabstop=2:
source ../../../trapexit.sh
(
trapexit -q <<-'EOF'
echo Hello World!
EOF
source enable.sh
enable sleep
sleep 10
#echo "$?"
)
$ ./main_INT.sh
^C
$ source enable.sh
$ enable sleep
$ help sleep
sleep: sleep seconds[.fraction]
Suspend execution for specified period.
sleep suspends execution for a minimum of SECONDS[.FRACTION] seconds.
On Mon, Dec 17, 2018 at 1:57 PM Peng Yu <pengyu...@gmail.com> wrote:
>
> Note that when SIGINT is set, whether an external or built-in sleep is
> used will not result in any difference.
>
> If I use some other method (say a for loop) instead of built-in sleep
> to introduce a delay, the EXIT can be reached upon ctrl-c. So this
> sounds like that the builtin sleep somehow causes the problem. Is it
> the case?
>
> $ cat main_builtin_INT.sh
> #!/usr/bin/env bash
> trap 'echo at EXIT' EXIT
> trap 'echo at SIGINT' SIGINT
> enable -f ~/Downloads/bash-4.4/examples/loadables/sleep sleep
> sleep 10
> $ cat \(/main_builtin_INT.sh
> #!/usr/bin/env bash
> (
> trap 'echo at EXIT' EXIT
> enable -f ~/Downloads/bash-4.4/examples/loadables/sleep sleep
> sleep 10
> )
> $ ./main_builtin_INT.sh
> ^Cat SIGINT
> at EXIT
> $ '('/main_builtin_INT.sh
> ^Cat SIGINT
> at EXIT
>
> $ cat ./main_builtin_for.sh
> #!/usr/bin/env bash
> (
> trap 'echo at EXIT' EXIT
> for ((i=0;i<100000;++i)); do
> :
> done
> )
> $ ./main_builtin_for.sh
> ^Cat EXIT
>
> On Mon, Dec 17, 2018 at 1:41 PM Peng Yu <pengyu...@gmail.com> wrote:
> >
> > Hi,
> >
> > See the follow code, '(/main_builtin.sh' behaves differently from the
> > other three scripts upon receiving ctrl-c. This is counter-intuitive.
> > I'd expect whether a built-in command called the result should be the
> > same.
> >
> > How to understand why there is such a difference? Is there an easy
> > workaround to make the result the same as the other three?
> >
> > $ ./main.sh
> > ^Cat EXIT
> >
> > $ ./main_builtin.sh
> > ^Cat EXIT
> >
> > $ \(/main.sh
> > ^Cat EXIT
> >
> > $ \(/main_builtin.sh
> > ^C
> >
> > $ cat main.sh
> > #!/usr/bin/env bash
> > trap 'echo at EXIT' EXIT
> > sleep 10
> >
> > $ cat main_builtin.sh
> > #!/usr/bin/env bash
> > trap 'echo at EXIT' EXIT
> > enable -f ~/Downloads/bash-4.4/examples/loadables/sleep sleep
> > sleep 10
> >
> > $ cat '(/main.sh'
> > #!/usr/bin/env bash
> > (
> > trap 'echo at EXIT' EXIT
> > sleep 10
> > )
> >
> > $ cat '(/main_builtin.sh'
> > #!/usr/bin/env bash
> > (
> > trap 'echo at EXIT' EXIT
> > enable -f ~/Downloads/bash-4.4/examples/loadables/sleep sleep
> > sleep 10
> > )
> >
> > --
> > Regards,
> > Peng
>
>
>
> --
> Regards,
> Peng
--
Regards,
Peng
