c# - Marshalling double parameters with P/Invoke -

i have problem p/invoke call i'm trying do. have call c++ class c# program. have source of class did put in dll project , create export functions access it's main method. should enough need , keep things simple.

my export method looks :

extern "c" _declspec(dllexport) void inference(double *c1, double *c2, double *c3, double *result) {     /* somecode */ } 

this compiles, , can see export in dumpbin output.

now problem is, can't call method c# code because pinvokestackinbalance exception, telling me

this because managed pinvoke signature not match unmanaged target signature.

i tried calling method :

[dllimport("inferenceengine.dll")] extern static unsafe void inference(double *c1, double *c2, double *c3, double *result); 

i tried :

[dllimport("inferenceengine.dll")] extern static void inference(ref double c1, ref double c2, ref double c3, ref double result); 

... both possible ways documented on msdn no luck. have clue problem ?

thanks !

you should declare c++ function __stdcall, p/invoke default:

extern "c" _declspec(dllexport) void __stdcall inference(double *c1, double *c2, double *c3, double *result); 

it's possible leave c++ prototype alone , change p/invoke declaration:

[dllimport("inferenceengine.dll", callingconvention=callingconvention.cdecl)] 

cdecl isn't used p/invoke, because windows api stdcall.