HMENU hmenu 是什么含义呢？

Void CMainFrame::OnAdd()
{
CMenu *pMenu=GetMenu();
①HMENU hmenu;
Hmenu=CreatePopupMenu();
②pMenu->InsertMenu(2, MF_BYPOSITION|MF_POPUP,(UINT)hmenu,”子菜单” );
CMenu *psub1=new CMenu;
CMenu *psub=pMenu->GetSubMenu(2);
psub->InsertMenu(0,MF_BYPOSITION,ID_ITEM1,”ITEM1”);
psub->InsertMenu(1,MF_BYPOSITION|MF_SEPARATOR);
psub->InsertMenu(2,MF_BYPOSITION,ID_ITEM1,”ITEM2”);
CWnd::DrawMenuBar();
}

这是程序的功能是为ID_ADD映射处理函数，首先得到主菜单的指针，请问接下的①语句是什么含义？