Date: Sat, 12 Apr 1997 12:37:31 +1000 (EST) From: Darren Reed <avalon@coombs.anu.edu.au> To: terry@lambert.org (Terry Lambert) Cc: hackers@freebsd.org Subject: Re: detecting kernel version at compile time Message-ID: <199704120244.TAA09699@freefall.freebsd.org> In-Reply-To: <199704110018.RAA10243@phaeton.artisoft.com> from "Terry Lambert" at Apr 10, 97 05:18:14 pm
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In some mail from Terry Lambert, sie said: > > > Lets see...firstly, there is <osreldate.h> which is particular to FreeBSD. > > Including that file always requires #ifdef's for FreeBSD. Now you want > > to introduce <sys/osreldate.h>. That is going to be conditional on what > > is in <osreldate.h>. THen code which currently checks for __FreeBSD_version > > must be adapted to see if __FreeBSD_sysversion exists. > > 1) <sys/xxx.h> files can *never* depend on <xxx.h> files. > 2) You only have to check the version if you want to protect > against a crash better than you currently do. > > Why weren't __FreeBSD_version & __FreeBSD_sysversion (IF you need both) put > > in <sys/param.h> ? For starters, one doesn't need to worry about extra > > include files, although removing <osreldate.h> would not be good, now. > > I don't know; I've never used <osreldate.h>. It really only applies > to the installation insteance of the toolset, and the instances of the > API enacted by the standard (not system) include files, IMO. > > It seems to me that it's a concession to vendors who don't want to check > the BSD manifest constants across BSD platforms. Given this, are there any objections from anyone about putting __FreeBSD_sysversion in <sys/param.h> ? As for the BSD symbols, I use them wherever possible. > You can't possibly have a system component that reference <osreldate.h>, > since it's not accessable in the kernel build environment (this is the > problem he is talking about addressing). Hmmm, can __FreeBSD_sysversion be made the same value as __FreeBSD_version ? (or vice versa) > > Further still, there is the uselessness of __FreeBSD__ in some > > circumstances. > > That would be those vendor circumstances where vendors want all BSD's > to standardize on the same interfaces. The problem with __FreeBSD__ is that it is defined by cc - or gcc/pgcc. That is, it depends on what system the compiler is built, not what OS it is running on. Problem being, it impacts every compilation thereafter.
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