CODEWITHSUNDEEP
makefileinclude
Avi
Avi

Reputation: 31

Is it possible to include a file generated in previous stages of the Makefile?

Say I want to use the following Makefile:

config:
    echo "STR = YAY" > params

-include params

do_print: config
    echo $(STR)

For this to work I need to run make in two steps, first make config to generate the params file and only then I can run make do_print and it would print the YAY. I am looking for a way that running make do_print will be able to generate the params file , include it and execute the print in "one pass".

Thanks

Upvotes: 0

Views: 274

Answers (2)

G.M.
G.M.

Reputation: 12909

The main issue with your makefile as shown is that you don't provide make with the correct information re. dependencies. The following...

config:
    echo "STR = YAY" > params

tells make that running the commands will create/update the non-phony target named config. But it doesn't. It actually creates/updates a file named params. Since params is a real file and also the one you want to include just rename the target and adjust the rest of the makefile accordingly. In addition you need (I think?) to use a phony dependency to force the params rule to be executed every time make is invoked and to ensure params is only updated if necessary (to prevent an infinite loop). Try something like...

.PHONY: FORCE

params: FORCE
    echo "STR = YAY" > [email protected]
    diff -q $@ [email protected] || cp [email protected] $@

-include params

do_print: params
    echo $(STR)

Upvotes: 2

Altaf
Altaf

Reputation: 3086

If you dont't want to use another target , then you could use below, but am not sure about your usecase:

$(shell echo "STR = YAY" > params)
-include params

do_print:
    echo $(STR)

OR
As suggested by @Renaud Pacalet, you could change the name of your target

Upvotes: 0

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