Paul, What is the best way to override the default compiler? is this good practice:
CXX:=$(CROSS_COMPILE)$(CXX) thanks, TP On Mon, Apr 17, 2017 at 9:37 AM, Paul Smith <psm...@gnu.org> wrote: > On Mon, 2017-04-17 at 09:43 +0200, zosrothko wrote: > > Here a simple makefile that sets the variable CXX if not defined to > > $(FOO)g++ > > CXX ?=$(FOO)g++ > > > > test: > > @echo $(CXX) > > > > and the some stories > > > > fandre@Ubuntu-x64:~/make$ unset CXX > > fandre@Ubuntu-x64:~/make$ make > > g++ > > fandre@Ubuntu-x64:~/make$ make FOO=bar > > g++ > > fandre@Ubuntu-x64:~/make$ FOO=bar make > > g++ > > fandre@Ubuntu-x64:~/make$ export FOO=bar;make > > g++ > > > > Why CXX is never set to 'barg++' ? > > ?= only assigns a value if the variable has no value. > > However, CXX always has a value, because there's a default value set: > > $ make -pf/dev/null | grep ^CXX > make: *** No targets. Stop. > CXX = g++ > > If you had chosen a different value to set your variable to it may have > been more clear; using: > > CXX ?= $(FOO)bar > > you would still see output: > > fandre@Ubuntu-x64:~/make$ make > g++ > > so clearly your assignment is not having any effect at any time. > > _______________________________________________ > Help-make mailing list > Help-make@gnu.org > https://lists.gnu.org/mailman/listinfo/help-make > _______________________________________________ Help-make mailing list Help-make@gnu.org https://lists.gnu.org/mailman/listinfo/help-make
