Re: Help with differing build environments

[Chris Albertson]

This is covered in the manuals in more detail but in general the idea 
is that you get "configure" to test for some required API and if found
set a variable like "HAVE_FOOBAR" if libFOOBAR is found and usaable

Then inside your code you use a bunch of #if statemnets to either use 
the system API or yours.

#if HAVE_FOOBAR
#include <foo_bar.h>
#else
#include <My_foo_bar_replacement.h>
#endif

#if HAVE_FOOBAR
  var = SillyFunction(x);
#else
  var = MyRewiteOfSillyFunction(x);
#endif

Sometimes you can simply fall back to another function if one is
not available  Like using "fsync" if "fdatasync" is not available.
(older Solaris lacks fdatasync) but I would never write #if SOLARIS.
I'd use HAVE_FDATASYNC.


Geoffrey Huang wrote:
> Hi there,
>
> I have a question on how to use autotools in differing build environments.
>
> I'm working on a project that's meant to be a portable library.  On some 
> systems, I'll be using a set of APIs provided by the platform.  In these 
> cases, I want autotools to look for the system's header files for the 
> API's.  Likewise, I want autotools to look for the system-provided 
> .c-files for these API's.
>
> On other targets, the system doesn't provide the API's, so I want 
> autotools to use the code I've implemented in the portable library itself.
>
> How would I go about doing this?  I've considered using the 
> AC_CANONICAL_SYSTEM statement in configure.in to get me the target 
> system.  However, that directive only seems to recognize standard gnu 
> platforms.  Some of my platforms aren't standard.
>
> Then I considered using the AM_CONDITIONAL test to specify the system 
> type directly to the configure script, but I have doubts that this is 
> the best way.
>
> Anyhoo, I'd appreciate any help.
>
> -g
>
>
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