GreQueryClipRegion

GreQueryClipRegion returns the handle of the currently selected clip region, or NULL (if none exists).

This function can be hooked by the presentation driver.

Simulation support

This function is simulated by a handling routine in the graphics engine.

Syntax

GreQueryClipRegion(hdc, pInstance, lFunction)

Parameters

hdc (HDC) - input

Device context handle.

pInstance (PVOID) - input

Pointer to instance data.

lFunction (ULONG) - input

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

Return Code

rc (HRGN) - returns

This function returns the handle of the clip region:

• hrgn Region handle
• NULL Null handle (no region selected)
• HRGN_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_INV_HDC

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

Sample Code

#define INCL_GRE_CLIP
#include <os2.h>

HDC      hdc;        /*  Device context handle. */
PVOID    pInstance;  /*  Pointer to instance data. */
ULONG    lFunction;  /*  High-order WORD=flags; low-order WORD=NGreQueryClipRegion. */
HRGN     rc;         /*  This function returns the handle of the clip region: */

rc = GreQueryClipRegion(hdc, pInstance, lFunction);