Question

I have a C# application from which I am trying to send a parameter to a C++ function. However, I am getting the error (mentioned in the subject)

C# application:

static class SegmentationFunctions
{
[DllImport("MyApplication.dll", EntryPoint = "fnmain", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
        public static extern int fnmain(string search);
    }
}

public partial class MainWindow:Window
{
public MainWindow()
{
InitializeComponent();

string search = "test string here";
int scommand = SegmentationFunctions.fnmain(search);
}

C++ file.h

extern "C" QUERYSEGMENTATION_API int fnmain(char query[MAX_Q_LEN]);

C++ file .cpp

extern "C" QUERYSEGMENTATION_API int fnmain(char searchc[MAX_LEN_Q])
{

do something...

}

Answer 1

Dependency Walker can show you what functions are effectively exported from the DLL. You will be able to see if your fnmain is there at all, or it is _fnmain instead , or has a C++ decoration in its name.