CombineRgn32(3w)

Usage

INT32 CombineRgn32
(

HRGN32 hDest,

HRGN32 hSrc1,

HRGN32 hSrc2,

INT32 mode
);

CombineRgn32 (GDI32.19).

The behavior is correct even if src and dest regions are the same.