BMX-NG MinGW/GNU and C/C++ DLLs

BlitzMax Forums/Brucey's Modules/BMX-NG MinGW/GNU and C/C++ DLLs

RustyKristi

(Posted 2016) [#1]

I have done some basic C/C++ file imports but I was wondering how do you compile and link external DLLs, particularly int,float,string functions that takes a number of parameters and with the same int,float,or string type.

I only found Visual C++ Solutions so far for Vanilla.

Brucey

(Posted 2016) [#2]

You have a C++ DLL that you want to use with BlitzMax?

If it has been built with VS++ then you'll need to build a C-glue dll in VS and link your BlitzMax code to that - because VS and GCC C++ ABIs on Windows are not compatible.

RustyKristi

(Posted 2016) [#3]

Thanks, yes of course I will be using the same MinGW that I use with the NG. Anyway I think I figured it out but maybe if you still have some tips..

I got the C side example from here to test:
http://www.transmissionzero.co.uk/computing/building-dlls-with-mingw/

C Code:

/* add_basic.c

   Demonstrates creating a DLL with an exported function, the inflexible way.
*/
__declspec(dllexport) int __cdecl Add(int a, int b)
{
  return (a + b);
}

MinGW DLL Creation:

gcc -c -o add_basic.o add_basic.c
gcc -o add_basic.dll -s -shared add_basic.o -Wl,--subsystem,windows

BMX Code:

SuperStrict

Global Add:Int(a:Int,b:Int) "Win32"

Local lib:Byte Ptr = LoadLibraryA("add_basic.dll")
If lib = 0 Then	
	Notify "DLL-file not found!"
Else
	Add = GetProcAddress(lib, "Add")
EndIf

Print Add(2,3)

End

I tested only C but I guess that's where the C++ glue part you mentioned comes in.

Edit: Updated Post Title