Re: multi-threaded compiling

[Greg Wooledge]

On Mon, Mar 11, 2024 at 10:19:26PM +0100, Mischa Baars wrote:
> On Mon, 11 Mar 2024, 21:08 Kerin Millar, <kfm@plushkava.net> wrote:
> > The pid can be obtained with the -p option, as of 5.1. Below is a
> > synthetic example of how it might be put into practice.

I'd forgotten about that one.  A recent addition, and one I've never used
yet.

> > #!/bin/bash
> >
> > declare -A job_by status_by
> > max_jobs=4
> > jobs=0
> >
> > wait_next() {
> >         local pid
> >         wait -n -p pid
> >         status_by[$pid]=$?
> >
> 
> How exactly is this indexing implemented internally? Does a first number on
> index n take m bits (using a linked list) or does it take n * m bits (using
> realloc(3))?

"declare -A" makes it an associative array (hash table).

Without that declare -A, it would be a sparsely indexed array.

In either case, it doesn't just blindly allocate millions of bytes of
memory.  It uses something slimmer.