Re: seeking advice for a modular build system

[Ralf Wildenhues]

Hello Hans-Christoph, Robert,

* Hans-Christoph Steiner wrote on Tue, Mar 11, 2008 at 03:04:11PM CET:
>
> Ah, ok, I think I figured out what you mean.  I wasn't clear with my  
> initial description.  What I want to enable and disable with flags is  
> not which libraries are used for the building (i.e. --with)  but which 
> Pure Data libraries get built.
>
> Basically, the Pure Data project has about 30ish different libraries,  
> each with its own dependencies, named things like 'gem', 'pdp', 'zexy', 
> etc.  I want to be able to do this:
>
> ./configure --disable-pdp
>
> Then it will build all of the Pure Data libs except 'pdp'.  Also, 'pdp' 
> depends on a lot of other libraries, so it should enable/disable 'pdp' 
> based on which libraries are present in the system.
>
> Does that make sense?  I don't think it's a common arrangement, but not 
> so unusual.

This is a very common arrangement, and there are a few ways to go about
it.  A very complex example is what OpenMPI uses, a rather simple one
would be this untested example:

-- configure.ac snippet --
AC_ARG_ENABLE([pdp], [AS_HELP_STRING([--disable-pdp], [disable pdp library])
# foolib is needed by pdplib so
AC_CHECK_LIB([foolib], [foofunc], [], [enable_pdp=no])
AM_CONDITIONAL([ENABLE_PDP], [test "$enable_pdp" != no])

-- Makefile.am snippet --
if ENABLE_PDP
lib_LTLIBRARIES = libpdp.la
libpdp_la_SOURCES = foo.c ...
endif


Hope that helps.

Cheers,
Ralf