hdc (HDC) - input

Device context handle.

hrgn (HRGN) - input

Region handle.

pInstance (PVOID) - input

Pointer to instance data.

lFunction (ULONG) - input

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

rc (LONG) - returns

Return codes.

This function returns an integer (cHits) indicating, where appropriate, whether correlation hits were detected:

GPI_OK

Successful
GPI_HITS
Successful with correlate hit (returned by display drivers when the correlate flag is ON, and a hit is detected)
GPI_ERROR
Error
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_HDC_BUSY PMERR_HRGN_BUSY
PMERR_INV_HDC
PMERR_INV_HRGN
PMERR_INV_IN_AREA
PMERR_INV_IN_PATH
PMERR_REGION_IS_CLIP_REGION

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