How can i use windows api (SendMessage, FindWindow..)?

Hi! Guys.

I was use normally windows api ( sendmessage, findwindow ).
But I can’t use sendmessage and findwindow at version 4.15.

How can i use sendmessage, findwindow?

help me please…

thank.

os : windows 10
engine version : 4.15

FIRST:
#include “Windows/AllowWindowsPlatformTypes.h”
#include
#include “Windows/HideWindowsPlatformTypes.h”

THEN:
SendMessageA(m_hCamMoudle, WM_CLOSE, 0, 0);
or
SendMessageW(m_hCamMoudle, WM_CLOSE, 0, 0);