bug#77535: closed (timeout treats very short durations as `0`)

[GNU bug Tracking System]

Your message dated Fri, 4 Apr 2025 20:27:55 +0100
with message-id <a1cfeefb-ca6d-42a5-8701-8e8c0d607b87@draigBrady.com>
and subject line Re: bug#77535: timeout treats very short durations as `0`
has caused the debbugs.gnu.org bug report #77535,
regarding timeout treats very short durations as `0`
to be marked as done.

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-- 
77535: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=77535
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> --- Begin Message ---
>
>
>
> Subject: 
>
> timeout treats very short durations as `0`
>
>
>
>
> Date: 
>
> Fri, 4 Apr 2025 17:26:56 +0200
>
>
>
>
> Hi,
>
> Version: timeout (GNU coreutils) 9.6, Archlinux, x86-64.
>
> While playing with different duration parameters to `timeout`, I
> noticed that extremely short durations, like `1e-3000`, are rounded
> down to `0`. The problem is that `0` has a special meaning (disabling
> the timeout), so I don't think this is desired.
>
> All of these commands exit immediately:
> ```
> timeout 0.0001 cat
> timeout 1e-100 cat
> timeout 1e-300 cat
> timeout 1e-323 cat
> ```
>
> But these never exits:
> ```
> timeout 1e-324 cat
> timeout 1e-3000 cat
> ```
>
> As if we had typed:
> ```
> timeout 0 cat
> ```
>
> I think there is some logic in `printf` to handle float parsing
> underflow, so maybe this can be reused in `timeout` as well.
>
> Thanks,
>
>
>
> --- End Message ---
> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#77535: timeout treats very short durations as `0`
>
>
>
>
> Date: 
>
> Fri, 4 Apr 2025 20:27:55 +0100
>
>
>
>
> User-agent: 
>
> Mozilla Thunderbird Beta
>
>
>
>
> On 04/04/2025 16:26, Nicolas Boichat wrote:
> > Hi,
> >
> > Version: timeout (GNU coreutils) 9.6, Archlinux, x86-64.
> >
> > While playing with different duration parameters to `timeout`, I
> > noticed that extremely short durations, like `1e-3000`, are rounded
> > down to `0`. The problem is that `0` has a special meaning (disabling
> > the timeout), so I don't think this is desired.
> >
> > All of these commands exit immediately:
> > ```
> > timeout 0.0001 cat
> > timeout 1e-100 cat
> > timeout 1e-300 cat
> > timeout 1e-323 cat
> > ```
> >
> > But these never exits:
> > ```
> > timeout 1e-324 cat
> > timeout 1e-3000 cat
> > ```
> >
> > As if we had typed:
> > ```
> > timeout 0 cat
> > ```
> >
> > I think there is some logic in `printf` to handle float parsing
> > underflow, so maybe this can be reused in `timeout` as well.
>
> The following should avoid this issue.
>
> Marking this as done.
>
> thanks!
> Pádraig
>
> diff --git a/src/timeout.c b/src/timeout.c
> index 578d71070..6756cd888 100644
> --- a/src/timeout.c
> +++ b/src/timeout.c
> @@ -371,6 +371,10 @@ parse_duration (char const *str)
>        usage (EXIT_CANCELED);
>      }
>
> +  /* Clamp underflow to 1ns, as 0 disables the timeout.  */
> +  if (duration == 0 && errno == ERANGE)
> +    duration = 1e-9;
> +
>    return duration;
>  }
>
>
>
> --- End Message ---