Re: [PATCH] some systems don't have (and need) sys/select.h

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 24, 2008, 21:17 UTC
Message-ID: <7vk5ly9b51.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <20080124183446.GJ30676@schiele.dyndns.org>

Robert Schiele <rschiele@gmail.com> writes:

> The select stuff is already in sys/time.h on on some systems like HP-UX
> thus we should not include sys/select.h in that case.
>
> Signed-off-by: Robert Schiele <rschiele@gmail.com>

The patch looks good. I'd rather try to be a bit more helpful to people who want to port git to their system that is not HP-UX, though.

How about wording it like this?

Subject: pre-POSIX.1-2001 systems do not have <sys/select.h>

POSIX.1-2001 has declaration of select(2) in <sys/select.h>, but in previous version of SUS, it is declared in <sys/time.h>, which is already included in git-compat-util.h.

This introduces NO_SYS_SELECT_H macro in the Makefile to be set on older systems, to skip inclusion of <sys/select.h> that does not exist on them.

We could check _POSIX_VERSION with 200112L and do this automatically, but earlier it was reported that the approach does not work well on some vintage of HP-UX. Other systems may get _POSIX_VERSION itself wrong. At least for now, this manual configuration is safer.