[lmi] Fwd: Re: wx xrcdemo and --disable-gif

[Greg Chicares]

Resending because "yahoo" refused it the first time...

-------- Forwarded Message --------
Subject: Re: [lmi] wx xrcdemo and --disable-gif
Date: Mon, 14 Aug 2017 14:27:05 +0000
From: Greg Chicares <address@hidden>
To: Let me illustrate... <address@hidden>

On 2017-08-13 23:41, Vadim Zeitlin wrote:
> On Sun, 13 Aug 2017 16:54:56 +0000 Greg Chicares <address@hidden> wrote:

[...building wx samples in parallel...]

>  So it looks like it might be better to avoid writing loops at all, I
> wonder if something like the following would work:
> 
>       all clean distclean: $(SAMPLES_SUBDIRS)
> 
>       $(SAMPLES_SUBDIRS):
>               $(MAKE) -C $@ $(MAKECMDGOALS) $(.TARGETS)

That works if and only if I mark the subdirs as phony targets:

        .PHONY: $(SAMPLES_SUBDIRS)

With xfce's "CPU Graph", I see all 32 (virtual) CPUs at 100% for
most of the run. Timing it with the zsh 'time' builtin shows:
  1170.04s user 39.90s system 2842% cpu 42.566 total
where "2842% cpu" conforms what I saw in "CPU Graph", and
"42.566 total" is a wonderful improvement.

> (the last line tries to be compatible with both GNU and BSD makes).

I don't know why "$(.TARGETS)" worked with gnu make here (it's not
in the manual for make-4.2
  https://www.gnu.org/software/make/manual/make.html
and I'm still using only "GNU Make 4.0" anyway--maybe it's a legacy
feature that isn't documented anymore), but what's important is
that it actually did work.

I hadn't proposed using the '-C' option because it's not POSIX,
but it is indeed honored by BSD and GNU/Linux.