WinSetWindowPtr

This function sets a pointer value into the memory of the reserved window words.

Syntax

WinSetWindowPtr(hwnd, lb, pp)

Parameters

hwnd (HWND) - Input: Window handle.
lb (LONG) - Input: Zero-based index into the window words.; The units of b are bytes. Valid values are zero through (cbWindowData-4), where cbWindowData is the parameter in WinRegisterClass that specifies the number of bytes available for application-defined storage.; The value QWP_PFNWP can be used as the index for the address of the window procedure for the window.
pp (PVOID) - Input: Pointer value to store in the window words.

Returns

rc (BOOL) - returns: TRUE Successful completion; FALSE Error occurred.

Remarks

The index parameter is valid only if all of the bytes referenced are within the reserved memory.

Errors

Possible returns from WinGetLastError:

PMERR_INVALID_HWND (0x1001) An invalid window handle was specified.
PMERR_PARAMETER_OUT_OF_RANGE (0x1003) The value of a parameter was not within the defined valid range for that parameter.

Example Code

#define INCL_WINWINDOWMGR /* Or use INCL_WIN, INCL_PM, */
#include <os2.h>

HWND   hwnd;  /*  Window handle. */
LONG   lb;   /*  Zero-based index into the window words. */
PVOID  pp;  /*  Pointer value to store in the window words. */
BOOL   rc;  /*  Success indicator. */

rc = WinSetWindowPtr(hwnd, lb, pp);

This function retrieves a pointer value from the memory of the reserved window word.

MyWindowProc(HWND hwnd, ULONG msg, MPARAM mp1, MPARAM mp2)
{
MYINSTANCEDATA *InstanceData;  /* application defined structure */

    switch (msg) {
    case WM_CREATE:
        DosAllocMem(&InstanceData, sizeof(MYINSTANCEDATA), fALLOC);
        /* WindowProcedure initializes instance data for this window */
        .
        .
        /* set pointer to instance in window words */
        WinSetWindowPtr(hwnd, 0, InstanceData);
        break;

    case WM_USER + 1: /* application defined message */
        /* Window procedure retrieves instance data to   */
        /* process this message                        */

        InstanceData = WinQueryWindowPtr(hwnd, 0);
        .
        .

        break;
        .
        .

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