Re: multi-threaded compiling

[Greg Wooledge]

On Tue, Mar 12, 2024 at 10:33:36AM +0100, Mischa Baars wrote:
> bash -c 'set +m; seconds=1; for (( i=0;i<32;i++ )); do exit ${i} & done;
> sleep ${seconds}; for (( i=0;i<32;i++ )); do wait -p pid; e=${?}; echo
> "$(printf %3u ${i}) pid ${pid} exit ${e}"; done;'

"wait -p pid" is not correct here.  In that command, pid is an output
variable, and you have not specified any process IDs to wait for -- so
wait is going to wait for *all* of the children to finish, and you'll
get zero as the exit status:

$ help wait
    [...]

    Waits for each process identified by an ID, which may be a process ID or a
    job specification, and reports its termination status.  If ID is not
    given, waits for all currently active child processes, and the return
    status is zero.  If ID is a job specification, waits for all processes
    in that job's pipeline.