After initializing a DDF buffer with DdfInitialize, and loading a metafile with GpiLoadMetaFile, the example uses DdfMetafile to place a reference to the metafile in the DDF buffer. For a more detailed example and discussion of initializing DDF, see the DdfInitialize sample.

#define INCL_WINWINDOWMGR       /* General window management    */
#define INCL_WINMESSAGEMGR      /* Message management           */
#define INCL_DDF                /* Dynamic Data Facility        */
#define INCL_GPIMETAFILES       /* MetaFiles                    */
#include <os2.h>
#include <pmhelp.h>

#define MF_HWND   0
#define ACVP_HAB  4

MRESULT WindowProc( HWND hwnd, ULONG ulMsg, MPARAM mp1, MPARAM mp2 )
{
    HWND   hwndParent;
    HAB    hab;
    HWND   hwndInstance;    /* help instance window                 */
    HDDF   hDdf;            /* DDF handle                           */
    HMF    hwndMetaFile;    /* metafile handle                      */

    switch( ulMsg )
    {
    case HM_QUERY_DDF_DATA:
        /* get the help instance */
        hwndParent = WinQueryWindow( hwnd, QW_PARENT );
        hwndParent = WinQueryWindow( hwndParent, QW_PARENT );
        hwndInstance = (HWND)WinSendMsg( hwndParent, HM_QUERY,
                                 MPFROMSHORT( HMQW_INSTANCE ), NULL );

        /* Allocate 1K Buffer (default)  */
        hDdf = DdfInitialize(
                    hwndInstance,  /* Handle of help instance */
                    0L,            /* Default buffer size     */
                    0L             /* Default increment       */
                    );

        if (hDdf == NULLHANDLE)       /* Check return code       */
        {
            return (MRESULT)FALSE;
        }

        /* get hab for this window */
        if ((hab = (HAB)WinQueryWindowULong(hwnd, ACVP_HAB)) == NULLHANDLE)
        {
           return (MRESULT)FALSE;
        }

        /* Load the Metafile to display */
        if ((hwndMetaFile = GpiLoadMetaFile(hab, "SAMP.MET")) == NULLHANDLE)
        {
            return (MRESULT)FALSE;
        }

        /* Save MetaFile hwnd in reserved word */
        WinSetWindowULong(hwnd, MF_HWND, hwndMetaFile);

        if (!DdfMetafile(hDdf, hwndMetaFile, NULL))
        {
            return (MRESULT)FALSE;
        }

        return (hDdf);

    case WM_CLOSE:
        GpiDeleteMetaFile((HMF)WinQueryWindowULong(hwnd, MF_HWND));
        WinDestroyWindow(WinQueryWindow(hwnd, QW_PARENT));

        return (MRESULT)TRUE;
    }
    return WinDefWindowProc( hwnd, ulMsg, mp1, mp2 );
}