Re: make question (depend on content of a file)

[Colin S. Miller]

James wrote:
> The goal is to satisfy both (a) and (b):
>
> (a) the target(T) depends on a generated file(F) as well as
> on the content of the file (file F contains a list of files).
> (b) parallel make enabled
>
> content = $(shell cat F)
>
> T: F $(content)
>
> F:
>      Rule to generate F
>
>
> How do I do it?
> TIA
>
> James


One way to do this is to
1) make a rule to convert F into a makefile, containing rules to rebuild T
2) Make the import file dependant on F


So your make file will be

#/usr/bin/make -f
.PHONY all
all: myExe

include F.d
F.d: F
  echo -e "T:\tF " > F.d
  tr [:space:] \\040 >> F.d
  echo -e \\n >> F.d

T: F.d
  ...

myExe: T
  ...


Or something like this; it is untested.
The first time you run the makefile,
you will get a warning that F.d doesn't exist,
but it will then be generated.

BTW,
gcc can make the import rule with the -M family of options.


HTH,
Colin S. Miller




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