[racket] C++ Extensions and Classes

I'm not entirely sure that I follow, but if you're writing these
extension functions in C++, I believe you'll need to wrap their
prototypes in an extern(C) { ... } block so that they'll be given
un-mangled names for the linker to use.

On Thu, Feb 6, 2014 at 4:56 PM, Cody Eilar <cody.eilar at gmail.com> wrote:
> I understand that, the issue is that I have to provide three functions that
> are not static so that I can make my c++ code known to scheme. Those
> functions are:
>
> scheme_reload(Scheme_Env *env)
> scheme_initialize(Scheme_Env *env)
> scheme_module_name()
>
> Each one of these functions are known to the linker. Inside the Foo_ext.cpp
> file, I have these three functions implemented. But in order to use
> Bar_ext.cpp I have to implement them as well, which means I have multiple
> declarations to the same function. So my Bar_ext.cpp file would Ideally look
> something like this:
>
> Bar_ext.cpp
> scheme_reload(Scheme_Env *env)
> {
>  /* Bar _ext reload stuff */
>     Foo_ext.scheme_reload(env)
> }
>
> Currently, the only way I see to solve this is to use a bunch of ifdefs, but
> I was curious if there was a more elegant solution.
>
> Thanks!
>
> On Thu, Feb 6, 2014 at 2:48 AM, David T. Pierson <dtp at mindstory.com> wrote:
>>
>> On Wed, Feb 05, 2014 at 02:16:54PM -1000, Cody Eilar wrote:
>> > > But what I really want is:
>> > >
>> > > Foo_ext.h:
>> > >
>> > > func1_racket_ext() { /*... do racket stuff and run func1() */}
>> > >
>> > > /* Scheme initializes etc... */
>> > >
>> > >
>> > > Bar_ext.cpp:
>> > > #include "Foo_ext.h"
>> > >
>> > > func2_racket_ext() {/* ... do more racket stuff and run func2() /*}
>>
>> Disclaimer: I know nothing about Racket extensions.
>>
>> In C++, if you want to be able to call a function from multiple .cpp
>> files, you typically put the *declaration* in a header:
>>
>>   void func1_ext(void);
>>
>> The definition would still go in a .cpp file:
>>
>>   void func1_ext(void)
>>   {
>>     /*...*/
>>   }
>>
>> You typically only put the definition in a header if you want to make an
>> inline function.  It doesn't seem like you want an inline function here.
>>
>> Does that help?
>>
>> David
>
>
>
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