Hello D community!!!
I'm porting the NVIDIA CUDA headers to D. The CUDA platform runs on multiple
OS, so functions prototypes (in the D way) are declared as "extern(Windows)
..." for MS Windows and "extern(C) ..." for other OS'es.
The thing is that there's no "alias extern(X) myextern;" in D to be used like
this:
version(Windows)
alias extern(Windows) myextern;
else
alias extern(C) myextern;
...
myextern void cudaFunct1();
myextern uint cudaFunct2(byte*);
...The C way to accomplish this is:
#ifdef _WIN32
#define CUDAAPI __stdcall
#else
#define CUDAAPI
#endif
...
CUresult CUDAAPI cuInit(unsigned int Flags);
It is a bit redundant and dirty to declare all the functions twice. So i made
a template to declare functions prototypes with the corresponding naming
convention, here's what i got:
template CUDAAPI(R, P ...)
{
version(Windows)
alias extern(Windows) R function(P) CUDAAPI;
else
alias extern(C) R function(P) CUDAAPI;
}
...
CUDAAPI!(CUresult, uint) cuInit;
This code actually compiles since its syntax is correct but when linking i
relize that the linker is still looking for the "extern(D)" symbol and by any
means, no matter where i place the extern(X), the compiler is generating the D
mangled symbol (_D5cudad4cuda6cuInitPWkZE5cudad4cuda8CUresult, at least the
template is inserted in the context).
I've tried with DMD 1.030 and the latest 1.069, both with the same result.
I also did a mixin flavored template that also compiles but is even worse
because the linker is still stuck with a templated/D mangled symbol, take a
look:
template CUDAAPI(string N, R, P ...)
{
version(Windows)
mixin("extern(Windows) R " ~ N ~ "(P);");
}
...
mixin CUDAAPI!("cuInit", CUresult, uint);
The generated symbol for this code is:
__D5cudad4cuda55__T7CUDAAPIVG6aa6_6375496e6974TE5cud
ad4cuda8CUresultTkZ6cuInitWkZE5cudad4cuda8CUresult@4. As you can see, the
symbol is still recognized as a template so i discard this code.
I found templates to be a very interesting case of study, templates give
languages the fun or the exciting part of programming by presenting challenges
in code complexity but still i can not get some parts of my code to work.
Any aproach or ideas on how to accomplish this template or multi extern
declaration?
Thank you so much for reading.
