Forum Discussion

Andreas_1's avatar
Andreas_1
15 years ago

Call C DLL from js

Im trying ta access a routine in a C DLL but cant get the call right. The code ive tried this far is like this: function testsDLLCall() {     var Def_Enviroment, Def_DLL, pointerd...
AlexeyK's avatar
AlexeyK
Icon for Alumni rankAlumni
15 years ago

Victor,


As far as I can see, the function declaration in the script code does not match the C function declaration.

Your C function uses two parameters: char * and int *, and returns an int value --


DD_WRAPPER_API int getDataInt(char* signalName, int* result);


Your script code is --




Def_DLL.DefineProc("getDataInt", VT_LPSTR ,VT_BYREF | VT_PTR);


I suggest changing this script line in the following way --




Def_DLL.DefineProc("getDataInt", vt_lpstr, vt_byref | vt_int, vt_int);


Also, as Alexei wrote, DLL functions must use the stdcall convention. I don't know if DD_WRAPPER_API in your code corresponds to stdcall, but in order for you to be able to call this function, it should correspond to it.