hwnd (HWND) - input

Window handle.

If this window is of any of the preregistered WC_* classes the class name returned in the PCHBuffer parameter is in the form "#nnnnn", where "nnnnn" is a group of up to five digits that corresponds to the value of the WC_* class name constant.

lLength (LONG) - input

Length of PCHBuffer.

It must be greater than 0.

PCHBuffer (PCH) - output

Class name.

If the class name is longer than (lLength-1) only the first (lLength-1) characters of class name are copied.

lRetLen (LONG) - returns

Returned class name length.

This is the length, excluding the null-termination character.