On Sunday 06 August 2006 12:58, Richard Andrews wrote: > --- Jeff Dike <[EMAIL PROTECTED]> wrote: > > On Sat, Aug 05, 2006 at 05:45:33PM +0200, Jax wrote: > > > > $ ARCH=um make linux > > > > > > make linux ARCH=um > > > > These should be the same. In one case, it's in the environment and in > > the other, it's on the command line, but it's all the same to the build. > > I've seen that they aren't the same in some contexts. Not kernel specific > contexts either. > > It's a GNU make thing. One (env first) is setting an environment and one > (env after make) is setting a makefile variable. The two are not the same. > I haven't gotten to the bottom of why; I suspect it comes down to when make > falls back to environments to fill missing make variables.
Environment variables _are_ imported but ARCH = ... overrides it, while ARCH ?= ... does not. In make linux ARCH=um, instead, ARCH=um overrides any assignment in Makefiles, except override ARCH = ... and (for this one I only guess) assignments like CFLAGS += ... > ...also: > A=thing make > has an environment flow-on effect to all children of make; whereas "make > A=thing" does not unless make so chooses. Yes, probably an export is needed, I'm not sure; in most situations (aka well-written makefiles), though, this should not make a difference (i.e. if submakefiles need a var it should be exported by the top Makefile). -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ User-mode-linux-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
