Re: multi-threaded compiling

On Mon, Mar 11, 2024 at 06:51:54PM +0100, Mischa Baars wrote:
> SECONDS=5; for (( i=0;i<32;i++ )); do { exit ${i}; } & pid[${i}]=${!}; done; sleep ${SECONDS}; for (( i=0;i<32;i++ )); do wait -n ${pid[${i}]}; e=${?}; echo "$(printf %3u ${i}) pid ${pid[${i}]} exit ${e}"; done;
> /bin/bash: line 1: wait: 1747087: no such job
>   0 pid 1747087 exit 127
> /bin/bash: line 1: wait: 1747088: no such job
>   1 pid 1747088 exit 127

Without analyzing this in depth, one thing struck me immediately:
you're using the reserved variable SECONDS, which has special semantics
in bash.  ${SECONDS} is going to expand to an ever-increasing number,
beginning with 5 (since that's the value you assigned), and going up
by 1 per second that the script runs.  I'm assuming that was not your
intention.

In general, any variable whose name is all capital letters *may* have
special meaning to the shell and should not be used for general storage
purposes in scripts.