GpiQueryElementType

This function returns information about the element to which the element pointer currently points.

Syntax

GpiQueryElementType(hps, plType, lLength, pszData)

Parameters

hps (HPS) - input

Presentation-space handle.

plType (PLONG) - output

Element type.

The element type can be system-defined or application-defined; see GpiElement and GpiBeginElement.

lLength (LONG) - input

Data length.

Length of the description data buffer.

pszData (PSZ) - output

Description of data buffer.

The description may be system-defined or application-defined; see GpiElement and GpiBeginElement. The string is null-terminated, even if it has to be truncated.

Return Value

lReqLength (LONG) - returns

Size of the data required to hold the element content.

This can be used for a subsequent GpiQueryElement function.

>=0

Size of data

GPI_ALTERROR

Error.

Remarks

This function is only valid when the drawing mode (see GpiSetDrawingMode) is set to retain (not draw-and-retain), and a segment bracket is currently in progress. It is not valid in an element bracket.

Errors

Possible returns from WinGetLastError:

PMERR_INV_HPS (0x207F)

An invalid presentation-space handle was specified.

PMERR_PS_BUSY (0x20F4)

An attempt was made to access the presentation space from more than one thread simultaneously.

PMERR_INV_MICROPS_FUNCTION (0x20A1)

An attempt was made to issue a function that is invalid in a micro presentation space.

PMERR_NO_CURRENT_ELEMENT (0x20E5)

An attempt has been made to issue GpiQueryElementType or GpiQueryElement while there is no currently open element.

PMERR_NOT_IN_RETAIN_MODE (0x20E2)

An attempt was made to issue a segment editing element function that is invalid when the actual drawing mode is not set to retain.

PMERR_INV_LENGTH_OR_COUNT (0x2092)

An invalid length or count parameter was specified.

PMERR_INV_IN_ELEMENT (0x2089)

An attempt was made to issue a function invalid inside an element bracket.

PMERR_NO_CURRENT_SEG (0x20E6)

An attempt has been made to issue GpiQueryElementType or GpiQueryElement while there is no currently open segment.

Example Code

#define INCL_GPISEGEDITING /* Or use INCL_GPI, INCL_PM, */
#include <os2.h>

HPS   hps;        /* Presentation-space handle. */
PLONG plType;     /* Element type. */
LONG  lLength;    /* Data length. */
PSZ   pszData;    /* Description of data buffer. */
LONG  lReqLength; /* Size of the data required to hold the element content. */

lReqLength = GpiQueryElementType(hps, plType, lLength, pszData);

This example uses the GpiQueryElementType function to retrieve the size of the current element. The size is used to retrieve the graphics-order data in the element.

#define INCL_GPISEGEDITING /* GPI Segment Edit functions */
#include <os2.h>

HPS hps; /* presentation space handle */
BYTE abElement[512];
LONG cbElement;
LONG lType;

/* move pointer to first element in segment */
GpiSetElementPointer(hps, 1L);

cbElement = GpiQueryElementType(
    hps, /* presentation space */
    &lType, /* variable to receive type */
    0L, /* copy zero bytes of description */
    NULL); /* no buffer for description */

GpiQueryElement(hps, 0L, cbElement, abElement);