Re: writing a macro to process subdirectories

[Robert P. J. Day]

On Fri, 7 Jan 2005, John Graham-Cumming wrote:

> You could achieve this with a target specific variable like this:
>
>   SUBDIRS = d1 d2 d3
>
>   .PHONY: subdirs ${SUBDIRS} clean configure
>   subdirs: ${SUBDIRS}
>
>   ${SUBDIRS}:
>         ${MAKE} -C $@ $(SUBDIR_GOAL)
>
>   d1: d2              # potential subdir dependency
>
>   clean: subdirs
>   clean: SUBDIR_GOAL=clean
>
>   configure: subdirs
>   configure: SUBDIR_GOAL=configure
>
> Target specific variables are available in the prereqs of a target so
> SUBDIR_GOAL will be set appropriately by the clean and configure targets
> and then can be used in the subdirs.
>
> Or if you know that you are only going to use one of these specific
> targets like clean or configure on the command-line you could do:
>
>   SUBDIRS = d1 d2 d3
>
>   .PHONY: subdirs ${SUBDIRS} clean configure
>   subdirs: ${SUBDIRS}
>
>   ${SUBDIRS}:
>         ${MAKE} -C $@ $(MAKECMDGOALS)
>
>   d1: d2              # potential subdir dependency
>
>   clean: subdirs
>   configure: subdirs

actually, thinking about it for a few more minutes led me to believe
that i may be asking too much here.  for example, the subdirectory
dependencies almost certainly won't be the same from target to target.

if i'm configuring or building, i might have some subdir dependencies.
but if i'm just cleaning, chances are, subdir dependencies won't
exist.

i'll think about this a bit longer, but maybe i'm just being a bit too
ambitious.

rday