Thread: How to define function pointer

The Function Pointer Tutorials - Index

You might also want to check that you are loading the right library. The names "dll1.dll" and "dlll.dll" look a lot alike in code (one reason why some style guides actively discourage using names containing the letter l and the digit 1). If you are loading a wrong dll, it will probably not export the function you want to call.

Originally Posted by leetow2003

Look:
I write codes in file DLL(name dll1.dll),

Code:

extern "C" _declspec(dllexport) int __stdcall ret()
{
        return 100;
}

and then I want to use this function:

Code:

typedef int (__stdcall FUN)();
        FUN *fun=NULL;

        HMODULE hmod=LoadLibrary("dll1.dll");
        if(NULL==hmod)
        {
                printf("error load\n");
                return -1;
        }
        fun=(FUN*)GetProcAddress(hmod,"ret");
        if(NULL==fun)
        {
                printf("error GetProcAddress:%d\n",GetLastError());
                return -1;
        }

but error number of function GetProcAddress is 127,
I want to know How to correct?

First read this... Dynamic-Link Libraries (Windows) ... yes, ALL of it.

Now create a proper DLL entry point with DLLMain().
Export your functions using DLLEXPORT tags.
Write an include file (.h) for the DLL's functions using DLLIMPORT tags.
Compile the DLL as a separate project.

Include the DLL's .h file in your main code.
Call LoadLibrary() and check it's return value to be sure it loaded.
Use your functions just like they were local in your .c file.

You do not need GetProcAddress() to use functions in Windows DLLs.