Question

Here is the context :

I am working on a makefile to create a .h at every build, including another makefile that will use this header. I can’t edit the second one.

Using a target all depending on my file, it compiles the first time, creating the missing MyHeader.h. The problem is, when I recompile, the header is not regenerated…

My makefile looks like this :

all: myHeader.h

myHeader.h:
    scriptToBuildMyHeader.sh

include obscureAndPrivateMakefile.make

I also tried with a .phony target at the beginning. Same result : once created, it won’t be regenerated at every build.

PS : I can’t call a script before make.

Do some makfile-Masters have any ideas how to deal with that ?

Thanks!

Answer 1

Because myHeader.h has no dependencies, it will never be rebuilt once it exists. You can work around this by creating a dependency from myHeader.h to a phony target, eg:

forcebuild:
    # dummy; do nothing and don't create this file
.PHONY: forcebuild
myHeader.h: forcebuild
   scriptToBuildMyHeader.sh

This will however slow down your build considerably, as the header (and any source files including it) will need to be rebuilt every time.