On Fri, Jul 05, 2013 at 04:12:30PM +0530, Ramkumar Ramachandra wrote: > Al Viro wrote: > > [...] > > IOW, any make variable (== macro in POSIX quote above) can be explicitly > > set in make(1) command line in form name=value and in that case nothing in > > makefile(s) can change its value. It's true for GNU make, it's true for > > BSD make and it's been true for historical Unix make since its introduction > > in v7. > > Thanks Al, the education is much appreciated. I always thought = > would override it, and ?= was for default value.
?= is a different story - it refuses to override _any_ earlier declarations, including ones in makefile itself. GNU make has added it fairly late, BTW - in 3.77 (1998); BSD make has grown it at some point during the rewrite Adam de Boor had been doing in late 80s. NFI whether he'd invented it or picked it elsewhere - there had been a lot of cross-pollination between the variants of make(1) all along... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
