[Omake] autoconf-style configure-time options

[Erick Tryzelaar]

Aleksey Nogin wrote:
> On 30.05.2007 20:14, Erick Tryzelaar wrote:
>
>> As far as I can tell, .STATIC blocks are run before omake processes 
>> the command line. 
>
> That's not quite true. The first time you run omake for that file (or 
> if you run "omake --configure"), the static sections would run the 
> exact same way as a "section ... export" section would. The only 
> difference is that the exported values would then be saved (to the 
> corresponding .omc file) and the _next_ time you run omake, the static 
> section will be skipped and the values will simply be loaded from the 
> .omc.

But if I have an OMakeroot like this:

open Configure/Fam
DefineCommandVars()
...

the Fam's static section will run before DefineCommandVars, right?

>> I believe this means that you can't, say, "omake ENABLE_VSNPRINTF=0" 
>> on the command line to skip testing if vsnprintf exists. Is there any 
>> way to do this? 
>
> You can have overrides (that consult either command-line variables or 
> the environment variables) explicitly coded in your files. You might 
> include the override in the static section (so that the tests are not 
> even performed when the overrides are in effect) - note that the way 
> things currently are implemented this will capture whatever the 
> overrides were the first time you ran omake. You might prefer to let 
> the static section do its thing and then allow overriding the results 
> (we do this in part in omake self-builds - the static sections figure 
> out whether fam/readline/etc is available, and the .config file 
> decided whether to actually use them). Or you can do both...

How can I access the command line variables without calling 
DefineCommandVars? I couldn't find any other primitive that can query 
the passed in arguments.

>> I'm trying to figure out how to do cross compiling, and I think we'd 
>> need something like this in order to do it.
>
> Note that most of the tests in our configure files should be 
> cross-compilation-friendly. As long as you only try to compile/link, 
> but do not try to actually run, the tests should do the right thing 
> w.r.t. figuring out the _target_ configuration (you may have to run 
> with --configure every time you switch the target platform :-( ; this 
> will go away in what's currently called the 0.9.8.x branch, but may 
> end up getting renamed).

But we have to run some programs :( Among other things, we need to be 
able to query C/C++ type size info, or have it manually specified.

Oh and one last thing. There isn't a way to add info to "omake --help" 
is there? If we provide a bunch of configure-time options, it'd be nice 
to be able to easily document what options are specified.

Thanks for all the help!