The InitializeProcessForWsWatch function initiates monitoring of the working set of the specified process. You must call this function before calling the GetWsChanges function.
BOOL InitializeProcessForWsWatch(
HANDLE hProcess // handle to the process
);
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. To get extended error information, call GetLastError.
Process Status Helper Overview, PSAPI Functions, EnumProcesses, GetWsChanges