Using Run-Time Dynamic Linking

[kshea]

Hi All:

I'm trying to use Run-Time Dynamic Linking. I defined a function type and a function variable. Then I load the library into memory, and set up the above function for run time loading, like the following:
//Function example: int count()

typedef int (*FUNC)()
...
HINSTANCE hinstLib;
hinstLib=LoadLibrary("mydll.dll"
FUNC func1;
if(hinstLib!=NULL)
{
func1=(func1type)GetProcAddress(hinstLib,"func1"
};

But if the function is an interface function, such as
STDMETHOD(Count)(/*[out]*/long *plCount)..., I used

typedef HRESULT (*FUNC)(Long); and got the error message that the specified procedure could not be found.

Does anyone have a clue to define this kind of function?

Thanks in advance.

Kay

 

[Temps]

I don't think it's a problem with the typedef definition - it would give a different error.

The error message means that GetProcAddress cannot find the function name you're passing in - check the dll's exported functions to ensure you've got the right function name.

 

[tchouch]

An example: Function gethostbyaddr() is in DLL ws2_32.dll. To dynamic link it, You can use that:

typedef HOSTENT* (__stdcall *PFNGETHOSTBYADDR)(char*, int, int);

PFNGETHOSTBYADDR pgethostbyaddr = NULL;
HINSTANCE hinst = LoadLibrary("ws2_32.dll"
if(hinst) {
//Sockets 2 - import
pgethostbyaddr = (PFNGETHOSTBYADDR)GetProcAddress(hinst, "gethostbyaddr"
if(pgethostbyaddr) {
//Call it
HOSTENT *pHostEnt= pgethostbyaddr( ...'Your arguments'...);
}
FreeLibrary(hinst);
}

 

[kshea]

Thank you both. [Temps] sir, you are right.
Helpful example, tchouch.

kay