Seriously, use std::thread
:
class CLASS
{
public:
void A();
private:
void B(your args go here);
};
void CLASS::A()
{
std::thread t(&CLASS::B, this, your args go here);
// when done
t.join();
// or
t.detach();
}
Explanation
Your code doesn't compile because CreateThread
is a C API, expecting a non-member C function as a callback. In order to call a non-static member function of a C++ class, the caller needs to know about this
pointer and how to correctly use it. Since WinAPI clearly doesn't have this
and doesn't expect a member function pointer, this cannot possibly work. Your compiler catches this and reports it as a type mismatch error.
This is where the lpParameter
of CreateThread
comes into play. It allows you to pass this
through that parameter. However it doesn't change the fact that CreateThread
doesn't know how to call C++ member functions. Therefore it's your responsibility to wrap it in a static function that will do the member function call:
class CLASS
{
public:
void A();
private:
DWORD B();
static DWORD s_B(LPVOID);
};
DWORD CLASS::s_B(LPVOID that) {
return ((CLASS*)that)->B();
}
void CLASS::A() {
CreateThread(NULL, 0, s_B, this, 0, NULL);
}
This is what @Nawaz does in their answer, except in a slightly more general way.
Even though this approach works, it clearly has downsides:
- It's verbose.
- It's non portable.
- You need to pass your original
args
through different means (e.g. through a member of your class).
std::thread
already does all that for you.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…