<div dir="ltr">Hmmm, I haven't had to wrap anything using extern C because all the function prototypes are in C already I believe (the three I mentioned above). The main idea here is that I want to reuse my extensions in the same way that my classes are constructed. I want to write extensions separately for each class that I have already written in C++. I have already successfully written my extension for Foo. I can load Foo_ext.rkt in my racket script and execute all the functions that I need. The issue is that I have another class, Bar, that inherits from Foo. So as it stands now, I can't figure out how to write my Bar extension such that I don't have to rewrite (or copy and paste) all the code from my Foo extension. I'd like to leverage the fact that I already wrote the extension for Foo and Bar is just a few extra variables and functions. I hope this clearly illustrates my goal. Thanks :-) </div><div class="gmail_extra"> <div class="gmail_quote">On Thu, Feb 6, 2014 at 12:17 PM, Jon Zeppieri <<a href="mailto:zeppieri@gmail.com" target="_blank">zeppieri@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">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. <div><div class="h5"> On Thu, Feb 6, 2014 at 4:56 PM, Cody Eilar <<a href="mailto:cody.eilar@gmail.com">cody.eilar@gmail.com</a>> 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 <<a href="mailto:dtp@mindstory.com">dtp@mindstory.com</a>> 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 > > > </div></div>> ____________________ > Racket Users list: > <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> > </blockquote></div> </div>