Re: jobs builtin inside SIGCHLD trap doesn't clean up terminated jobs

[Chet Ramey]

On 4/25/23 2:41 PM, Guldrelokk wrote:
> POSIX has the following to say with respect to the 'jobs' utility:
> > When jobs reports the termination status of a job, the shell shall remove
> > its process ID from the list of those known in the current shell
> > execution environment
> With Bash, this is not the case for 'jobs' called from within a SIGCHLD
> handler.  This can be verified with:
> sh -c 'set -m; trap "jobs %cat; jobs %cat" CHLD; cat </dev/null & wait 
> %cat; jobs %cat; jobs %cat'

Thanks for the report. The jobs builtin now removes jobs from the jobs
list even inside traps, as POSIX requires.


> Because job tables are not inherited by subshells, capturing the output of
> 'jobs' requires using a named pipe, which is relatively cumbersome.

This is not quite true. Bash makes special provisions so you can use
command substitution, process substitution, or even a pipeline to get
the jobs list.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/