Function Tk_CreateWindowFromPath

micropolis-activity/src/tk/tkwindow.c:743–827

(interp, tkwin, pathName, screenName)

 *
 * Side effects:
 *	A new window structure is allocated locally.  An X
 *	window is not initially created, but will be created
 *	the first time the window is mapped.
 *
 *----------------------------------------------------------------------
 */

Tk_Window
Tk_CreateWindowFromPath(interp, tkwin, pathName, screenName)
    Tcl_Interp *interp;		/* Interpreter to use for error reporting.
				 * Interp->result is assumed to be
				 * initialized by the caller. */
    Tk_Window tkwin;		/* Token for any window in application
				 * that is to contain new window. */
    char *pathName;		/* Path name for new window within the
				 * application of tkwin.  The parent of
				 * this window must already exist, but
				 * the window itself must not exist. */
    char *screenName;		/* If NULL, new window will be on same
				 * screen as its parent.  If non-NULL,
				 * gives name of screen on which to create
				 * new window;  window will be a top-level
				 * window. */
{
#define FIXED_SPACE 5
    char fixedSpace[FIXED_SPACE+1];
    char *p;
    Tk_Window parent;
    int numChars;

    /*
     * Strip the parent's name out of pathName (it's everything up
     * to the last dot).  There are two tricky parts: (a) must
     * copy the parent's name somewhere else to avoid modifying
     * the pathName string (for large names, space for the copy
     * will have to be malloc'ed);  (b) must special-case the
     * situation where the parent is ".".
     */

    p = strrchr(pathName, '.');
    if (p == NULL) {
	Tcl_AppendResult(interp, "bad window path name \"", pathName,
		"\"", (char *) NULL);
	return NULL;
    }
    numChars = p-pathName;
    if (numChars > FIXED_SPACE) {
	p = (char *) ckalloc((unsigned) (numChars+1));
    } else {
	p = fixedSpace;
    }
    if (numChars == 0) {
	*p = '.';
	p[1] = '\0';
    } else {
	strncpy(p, pathName, numChars);
	p[numChars] = '\0';
    }