Thread: making a dll

Hello,

i'm trying to figure out how to make a dll that can be used by a diffrent program that is writion in a diffrent programming langwich i have had alook round the internet but i cna find how to do it.

btw i'm useing dev-c++

You'll then need to use LoadLibrary() and GetProcAddress(). There might be other ways but this is how I would do it; google them.

erm yeh thats how you load the dll into another program but i'm trying to also figgure out how to make it becuse i used dev-cpp dll and i couldnt get it to work btw i was trying to include it to vb6


thanks

you have to surround all the functions with extern "C" to prevent the compiler from mangling the names

Code:

#ifdef _cplusplus
extern "C" {
#endif
// your code here
#ifdef _cplusplus
}
#endif

Or just simply put the functions in a *.c file so that it gets compiled as C and not C++.

Don't forget to export the symbols

For more information google for Mixed Language Programming

ok thanks thats helpful but can anyone show me what a basic dll looks like so i know my one is right?

A basic dll has only one function -- DllMain() which is similar to main() in a normal C/C++ program. And you compiler will generate the code for that. You will want to manually create a header file that contains the prototypes of the functions you want to export. This is for other C/C++ programs that will use your dll, but won't probably need it for VB6. I don't know how you will declare the function in VB6.

This will export one function -- foo().

Code:

// This is the C source file
// includes here
#include <all includes here>

#ifdef __cplusplus
extern "C" {
#endif

__declspec( dllexport ) int foo()
{
   return 0;

}
#ifdef __cplusplus
}
#endif