Re: Breaking the 10-limit : Problems/Questions for Windows build

Hi, Mart, Wolf-Dieter and all.

>> I undersand that it could be big issue to break the pure-C interface,
>> so, I gave up the "std::vector" solution, and I'm currently working
>> on a pure-C one :
>> - the tModInfo array would be allocated on the heap by the module itself,
>>    at DLL load-time, in its "Module entry point" function
>>    (whose signature would become : extern "C" int xxx(tModInfo**))
>> - it would be freed by the module unloading functions in tgf lib.
> 
> I see a (small) problem with this. It is not given that the robot is compiled 
> with the same compiler as the rest of the code. If a piece of code is 
> allocated with the _tgf_win_malloc function in tgf.cpp, you can't free it 
> with the normal free function. So, in my opinion, it must be forced to use 
> the malloc function matching with the free function. I think that is best 
> done if the reallocation is done in a function.

Even better, may be :
- again, 2 kinds of modules :
   * the the current one, with a maximum of 10 interfaces
   * a new one, with unlimited nb of interfaces
- the first kind is totally unchanged
- the second kind keeps its 'extern "C" void <module name>(tModInfo*)' entry 
point, with usual implementation
   but it has a new 'extern "C" unsigned int <module name>_NbItf()' DLL function
   that simply returns the number of interfaces it publishes
   (= number of cars for a robot)

At module load time,
   1) TGF checks first for the second entry point
   2) if it finds it, it calls it and get the real number of interfaces
   3) if it does not find it, it assumes this number is MAX_MOD_ITF (10)
   4) then it dynamically allocates the array of tModInfo
      with the determined size, and pass it to the normal entry point

Advantages :
- no dynamic allocation by the modules => less potential issues with alloc/free
   done with different C libs ...
- even less changes in robots/modules code

Flaws :
- ??? => tell me !

Cheers,

Jean-Philippe.



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