How to get exit status of a shell command used in GNU Makefile?

Question

I have a makefile rule in while I am executing a linux tool. I need to check the exit status of the tool command, and if that command fails the make has to be aborted.

Answer 1

If all you want is for the make to be aborted iff the tool exits with a nonzero status, make will already do that by default.

Example Makefile:

a: b
    @echo making $@
b:
    @echo making $@
    @false
    @echo already failed

. This is what happens with my make:

$ make
making b
make: *** [Makefile:6: b] Error 1

Make sure partially or wholly created targets are removed in case you fail. For instance, this

a: b
    @gena $+ > $@
b:
    @genb > $@

is incorrect: if on the first try, genb fails, it will probably leave an incorrect b, which, on the second try, make will assume is correct. So you need to do something like

a: b
    @gena $+ > $@ || { rm $@; exit 1; }
b:
    @genb > $@