[cmake-developers] How to use JOB_POOLS?

[Brad King]

On 11/21/2016 11:06 AM, Dave Abrahams wrote:
> the documentation for JOB_POOLS is sparse

Yes, it is bare-bones reference documentation for someone that already
knows how Ninja job pools work.  A sufficiently motivated contributor
could add more to the `Help/generator/Ninja.rst` document in a new
"Job Pools" section.

> I understand the principle at work, but it's really unclear
> how JOB_POOL_LINK and JOB_POOL_COMPILE are supposed to work when set
> per-target.

They assign link rules and compile rules for that target to the
named pool.  Each pool can have a different size assigned in the
global JOB_POOLS property.  Different targets could be in different
pools, though typically the global settings are sufficient.

> I presume means compilation of languages that CMake knows about?

Yes.  It is for the compilation and linking commands that CMake
generates.

> what about custom targets?

We currently have no interface to assign custom commands or
custom targets to any pool, simply because no one implemented
such support.  It would have to be a new optional argument to
the add_custom_command and add_custom_target commands.

-Brad