compiler doesn't like CreateThread

ok, last one for the night, i swear....

essentially, all i'm trying to do is create a win32 thread with the CreateThread function

(for those not familiar w/ it)

Code:

HANDLE CreateThread (
                     LPSECURITY_ATTRIBUTES lpThreadAttributes, 
                     SIZE_T dwStackSize,
                     LPTHREAD_START_ROUTINE lpStartAddress,
                     LPVOID lpParameter,
                     DWORD dwCreationFlags,
                     LPDWORD lpThreadId  )

for whatever reason, the compiler is telling me that my function call does not match the definition of this function. i actually even tried copying someone's example code straight from a tutorial, and it's still giving me the same error message. anyway, here's my code:

Code:

    DWORD genericThread;
    HANDLE updateThread;
    char lszThreadParam[3]; 
    strcpy(lszThreadParam,"3");
    updateThread = CreateThread(NULL,0,CheckUpdates,&lszThreadParam,0,&genericThread);

.... any ideas??

maybe:

Code:

updateThread = CreateThread(NULL,0,CheckUpdates,lszThreadParam,0,&genericThread);

ok, just realized that it's called from within a class, so i thought maybe it was looking for a method in the class called CreateThread? maybe? i dunno.... i tried changing the function call to ::CreateThread and got a different error, saying "illegal implicit conversion from '__stdcall unsigned long (*) (void*)' to '__stdcall unsigned long (*) (void*)'".... which makes even less sense to me.... damn it....

Code:

DWORD WINAPI CheckUpdates(LPVOID lp)
{
	return 0;
}

int main()
{
   DWORD genericThread;
   HANDLE updateThread;
   char lszThreadParam[3]; 
   strcpy(lszThreadParam,"3");
   updateThread = CreateThread(NULL,0,CheckUpdates,lszThreadParam,0,&genericThread);
	
	return 0;
}

ok... i got something. basically i can't call a member function of a class in CreateThread:

from: <http://www.ciprian-miclaus.com/sources/win32threads.asp?id=1&tip=c>
(no intentions of plagiarizing here)

DWORD WINAPI ThreadProc(
LPVOID lpParameter
);

We'll notice this prototype will keep us from having this callback function as a member of a class, as it's member functions are passed a hidden parameter: this.


this page also provided a solution, but i didn't entirely understand it... and the code was a little sloppy too, i think. so i've identified the problem, but don't know how to solve it.... any more suggestions? please??? this thing is making me want to pull out my hair.

You can only call a static function of a class ( as it does not get passed a "hidden" this pointer ). Pass the class as parameter. In the static function, cast the parameter to an object of your class and invoke the function you originally wanted to call in a thread. Sounds more complicated than it is.

Be aware that many compilers had problems using CreateThread() if at the same time they used the standard c library. The problems were subtle resulting in small memory leaks which accumulated over time.

Most really modern compilers should have this fixed now, but there are a lot of people, me included, that have grown up wary of CreateThread() and routinely use beginthread() or beginthreadex() which never suffered from this problem.