c++ pointer to a function as argument - c++

Question

I have a C++ API with a cThread class, and this method to create a thread:
void cThread::start(void(*a_function)(void), CThreadPriority a_level);
I've done a class and a init() method to launch a thread and an updateHaptics() method to be executed by the thread:
void EntryClass::init()
{
typedef void (EntryClass::*method)();
method p;
p = &EntryClass::updateHaptics;
// create a thread which starts the main haptics rendering loop
cThread* hapticsThread = new cThread();
hapticsThread->start(p, CTHREAD_PRIORITY_HAPTICS);
}
void EntryClass::updateHaptics(void)
{
// ...
}
My problem is to pass the updateHaptics() method as an argument to the cThread::start() method.
I've got this error:
1>EntryClass.cpp(55): error C2664: 'void chai3d::cThread::start(void (__cdecl *)(void *),const chai3d::CThreadPriority,void *)' : impossible de convertir l'argument 1 de 'method' en 'void (__cdecl *)(void)'
REM: I'm under Windows 8/Visual Studio

Answer 1

The signature you indicated
void(*a_function)(void)
is for a function, not for a class method. A static method will work too
Note the difference with the typedef you used:
void (EntryClass::*method)();
The definition could be:
class EntryClass {
public:
void init();
static void updateHaptics(); // <--- NOTE the static
};
and your implementation
void EntryClass::init()
{
typedef void (*method)(); // <---- NOTE THIS CHANGE
method p;
p = &EntryClass::updateHaptics;
// create a thread which starts the main haptics rendering loop
cThread* hapticsThread = new cThread();
hapticsThread->start(p, CTHREAD_PRIORITY_HAPTICS);
}
void EntryClass::updateHaptics(void)
{
// ...
}

Answer 2

As I know, we can use only static function as a thread proc. Yes we can pass class static function also.