From: Lucas Gabriel Vuotto <lucas@sexy.is>
Subject: Re: make: -j without params
To: tech@openbsd.org
Date: Sat, 22 Feb 2025 18:57:19 +0000

On Sat, Feb 22, 2025 at 04:27:38PM +0100, Marc Espie wrote:
> I had quite a bit of fun with students this week, and stumbled upon
> getopt ::   extension.
> 
> Figured out, it would be obvious to do in make.
> 
> I looked at the others (very few instances) of tools that use ::
> to discern a pattern: in general, the consensus is that if we get an
> optarg, we whine if it doesn't match our expectation.
> 
> So here's a patch to have make -j use hw.ncpuonlines if there's no optarg.
> Might come in handy for people compiling on several machines who don't
> want to remember the details.
> 
> Wrt posix's compatibility, opengroup doesn't say anything.
> 
> And gmake -j does something (doesn't limit the number of jobs, from the doc)
> 
> 
> So, handy ? crazy ? not needed ?
> 
> 
> It's a very straightforward patch with an obvious failure path.

Personally, I don't like how optional args are handled: the argument is
now required to go right after the option letter, without space:
`make -j 4` doesn't work as it currently works anymore, and instead will
use all the online cpus and will try to build the target `4`.

The C part looks fine. The manpage does need an small adjustment to
reflect the previous comment (which is also reflected in some part of
POSIX [0], where optional args are shown as `-c option_argument 
-f[option_argument]`). btw, next section of POSIX, Utility Syntax
Guidelines, suggest against optional arguments.

[0]: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap12.html

	Lucas