How to pass function pointer as lpParameter to CreateThread? - c++

Question

I have the following function which will be called by CreateThread:
DWORD WINAPI start_thread(LPVOID handleFunction)
{
int prio = 4;
// call handleFunction()
handleFunction(prio);
return TRUE;
}
And I create the thread here:
DECL_PREFIX tid_t so_fork(so_handler *handleFunction, unsigned priority) {
DWORD dw;
hThr[currentThread] = CreateThread(
NULL, // default security attributes
0, // use default stack size
(LPTHREAD_START_ROUTINE)start_thread, // thread function name
(LPVOID)&handleFunction, // argument to thread function
0, // use default creation flags
&dw); // returns the thread identifier
return 0;
}
I get the following error when I am builind it:
Error C2064 term does not evaluate to a function taking 1 arguments libscheduler
expression preceding parentheses of apparent call must have (pointer-to-) function type libscheduler
What am I doing it wrong?

Answer 1

Passing &handleFunction to CreateThread() is wrong, because you are passing the local address of the handleFunction variable itself, not the address of the so_handler that it is pointing at.
Since handleFunction is already a pointer, try something more like this instead:
DWORD WINAPI start_thread(LPVOID handleFunction)
{
int prio = 4;
// call handleFunction()
so_handler *handler = (so_handler *) handleFunction;
handler(prio); // or maybe (*handler)(prio), depending on how so_handler is actually defined...
return TRUE;
}
DECL_PREFIX tid_t so_fork(so_handler *handleFunction, unsigned priority) {
DWORD dw;
hThr[currentThread] = CreateThread(
NULL, // default security attributes
0, // use default stack size
&start_thread, // thread function name
handleFunction, // argument to thread function
0, // use default creation flags
&dw); // returns the thread identifier
return 0;
}