Re: unwanted warning "execute_coproc: coproc [$PID:.*] still exists"

[Chet Ramey]

On 4/7/11 8:06 AM, sbrabec@suse.cz wrote:

> Bash Version: 4.1
> Patch Level: 10
> Release Status: release
> 
> Description:
>       Warning "execute_coproc: coproc [$PID:.*] still exists" as it is
>       implemented makes no sense. It appears in many situations where
>       it is done intentionally and it is not easy to silence it.
> 
>       If writing values of PID and I/O channels does not overwrite old
>       values, I see no reason to issue this warning.
> 
> Repeat-By:
>       coproc a ( cat )
>       coproc b ( cat )
>       bash: warning: execute_coproc: coproc [13690:b] still exists
> 
> Fix:
>       The warning should be issued only if the old process still
>       exists AND array which should store the coproc data is not
>       empty.

The warnings exist because there is really only one shell coproc
internally.  You can do a lot with the arrays and shell builtins, but
as the man page says under BUGS:

        There may be only one active coprocess at a time.

(The shell will forget about earlier coprocs and not mark them as
completed, for instance.)

There is some support for multiple coprocs, and if there is sufficient
need, I will finish it.  I'm waiting to see whether or not there is a
need for more than one simultaneous coproc -- I don't have a lot of
reports of coproc use.

Chet

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