Function Tk_CreateSelHandler

micropolis-activity/src/tk/tkselect.c:226–283

(tkwin, target, proc, clientData, format)

 *--------------------------------------------------------------
 */

void
Tk_CreateSelHandler(tkwin, target, proc, clientData, format)
    Tk_Window tkwin;		/* Token for window. */
    Atom target;		/* The kind of selection conversions
				 * that can be handled by proc,
				 * e.g. TARGETS or XA_STRING. */
    Tk_SelectionProc *proc;	/* Procedure to invoke to convert
				 * selection to type "target". */
    ClientData clientData;	/* Value to pass to proc. */
    Atom format;		/* Format in which the selection
				 * information should be returned to
				 * the requestor. XA_STRING is best by
				 * far, but anything listed in the ICCCM
				 * will be tolerated (blech). */
{
    register TkSelHandler *selPtr;
    TkWindow *winPtr = (TkWindow *) tkwin;

    if (winPtr->dispPtr->multipleAtom == None) {
	SelInit(tkwin);
    }

    /*
     * See if there's already a handler for this target on
     * this window.  If so, re-use it.  If not, create a new one.
     */

    for (selPtr = winPtr->selHandlerList; ; selPtr = selPtr->nextPtr) {
	if (selPtr == NULL) {
	    selPtr = (TkSelHandler *) ckalloc(sizeof(TkSelHandler));
	    selPtr->nextPtr = winPtr->selHandlerList;
	    winPtr->selHandlerList = selPtr;
	    break;
	}
	if (selPtr->target == target) {

	    /*
	     * Special case:  when replacing handler created by
	     * "selection handle" free up memory.  Should there be a
	     * callback to allow other clients to do this too?
	     */

	    if (selPtr->proc == HandleTclCommand) {
		ckfree((char *) selPtr->clientData);
	    }
	    break;
	}
    }
    selPtr->target = target;
    selPtr->format = format;
    selPtr->proc = proc;
    selPtr->clientData = clientData;
    if (format == XA_STRING) {
	selPtr->size = 8;
    } else {
	selPtr->size = 32;
    }