Re: multiple targets, different build options

[Peter Johansson]

John Richetta wrote:
> (I'm an autotools newbie.)
>
> What is the automake sanctioned way of providing different top-level 
> make targets, that build my application with different options?
>
> For example, say I want to build foo_nondebug, and foo_debug, and 
> (luckily) all of my application code resides in the subdirectories of 
> the top level directory containing the top-level Makefile.  Obviously, 
> if I invoke make from one of these targets, I can use the traditional 
> trick of passing a sub-make arguments (like FOO_DEBUG=-g or 
> FOO_DEBUG=<empty>).
I use the following snippet in one my projects:

AC_ARG_ENABLE(debug,
   [AS_HELP_STRING([--enable-debug],[turn on debug options and code])],
   [SD_CXXFLAGS="$SD_CXXFLAGS -g -O"],
   [SD_CPPFLAGS="-DNDEBUG" SD_CXXFLAGS="$SD_CXXFLAGS -O3"])

# Export flags
AC_SUBST([SVNDIGEST_CPPFLAGS], $SD_CPPFLAGS)
AC_SUBST([SVNDIGEST_CXXFLAGS], $SD_CXXFLAGS)

and then in each Makefile.am:

AM_CPPFLAGS = $(SVNDIGEST_CPPFLAGS)
AM_CXXFLAGS = $(SVNDIGEST_CXXFLAGS)

This will add a switch to configure so we can call ./configure 
--enable-debug when we wanna build in debug mode, and else ignore the 
option. Their is no dependency, so if I switch between the modes in the 
same builddir I need to issue make clean.

Hope this helps.

Cheers,
Peter