hdc (HDC) - input

Device context handle.

hrgnSrc1 (HRGN) - input

First region handle.

hrgnSrc2 (HRGN) - input

Second region handle.

pInstance (PVOID) - input

Pointer to instance data.

lFunction (ULONG) - input

High-order WORD=flags; low-order WORD=NGreEqualRegion.

rc (LONG) - returns

Return codes.

This function returns an integer (lEquality) indicating whether the regions are equal:

EQRGN_EQUAL

Equal
EQRGN_ERROR
Error
EQRGN_NOTEQUAL
Not equal
Possible Errors Detected: When an error is detected, the handling routine must call WinSetErrorInfo to post the condition. Error codes for conditions that the handling routine is expected to check include:

PMERR_HRGN_BUSY PMERR_INV_HRGN
PMERR_REGION_IS_CLIP_REGION

Refer to the "Error Explanations" section in the Presentation Manager Programming Reference for further explanation.