telling 'make' to ignore dependencies when the top target has been created

Question

I\'m running the following kind of pipeline:

digestA: hugefileB hugefileC
    cat $^ > $@
    rm $^

hugefileB:
    touch $@

hugefileC:
    touch $@
<         


        

Answer 1

If you mark hugefileB and hugefileC as intermediate files, you will get the behavior you want:

digestA: hugefileB hugefileC
        cat $^ > $@

hugefileB:
        touch $@

hugefileC:
        touch $@

.INTERMEDIATE: hugefileB hugefileC

For example:

$ gmake
touch hugefileB
touch hugefileC
cat hugefileB hugefileC > digestA
rm hugefileB hugefileC
$ gmake
gmake: `digestA' is up to date.
$ rm -f digestA
$ gmake
touch hugefileB
touch hugefileC
cat hugefileB hugefileC > digestA
rm hugefileB hugefileC

Note that you do not need the explicit rm $^ command anymore -- gmake automatically deletes intermediate files at the end of the build.