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makefilegnu-makejobs

Makefile $(eval ...) : what's the behavior when plutiple jobs run simultaneously?

I've defined the following rule:

$(OUTDIR)/%_sorted.bam:
    $(eval SAMPLE:=$(subst _sorted,,$(notdir $(basename $@))))
    (...) do something with $(SAMPLE)

can I use it safely (= is it a "local variable" to the rule ?) with 

make -j (number of jobs)

or does the variable $(SAMPLE) will be replaced for each (simultaneous) invocation of the rule ?

Solution

  • Yes, you can. GNU make expands the whole recipe prior to executing it. Job server mode only affects the execution of sub-processes spawned by make, everything else is single threaded.