Re: Recursive Make Considered Harmful (was: Re: executing a rule prior to any targets?)

[gk]

Hi Phillip,
Thanks for the ideas. I understand most of it.
I'm trying to generalize design for arbitrary languages and dependency 
generation tools, allowing flexibility of build modes, including 
'recursion' for those who want it. But rather than implementing sub-make 
recursion though, I think it is better to generate a single makefile for a 
subset of directories.
I think this is the only way that make can detect circular dependencies; 
sub-makes can loop infinitely.

I use a 'project' shell script to set the environment or specify other 
config files to source before doing a make.
My top level makefile is XMLMAKE_PROJECT_MAKEFILE; this includes default 
rule and pattern rules.

    - Default mode: build a single directory (and any prerequisites 
outside the directory)
    - 'xmlmake -P' option: build the entire project, non-recursively
    - 'xmlmake -X' option: build the current directory and all 
subdirectories, non-recursively
        ( 'xmlmake -X -C $XMLMAKE_PROJECT_DIR' is the same as 'xmlmake -P' )


At 03:01 PM 10/20/2002 -0700, you wrote:
> As mentioned above, instead of cd'ing and reinvoking make, I just
> set a variable and include the top-level makefile.  For example,
> here's what the GNUmakefile in the 'sys_utils' directory looks
> like:
>
>         THIS := sys_utils
>         TOP := $(patsubst %/${THIS},%,${CURDIR})
>         include ${TOP}/GNUmakefile
>
> The top line is the only thing that differs among the subdirectory
> GNUmakefiles.  (The 'THIS' variable is used to change the default
> target to only include the files 'below' where the make was invoked.)

Does your system allow specifying targets without a full path?
In other words, it would be nice to type:
$cd obj.platform/util/foo/; make bar.o

And have the makefile find the right dependencies, even though your .P 
makefile knows it as:
${TOP}/obj.platform/util/foo/bar.o: \
 ${TOP}/util/foo/bar.c \

- Greg Keraunen