Tk_SetClass - Man Page

set or retrieve a window's class


#include <tk.h>

Tk_SetClass(tkwin, class)



Tk_Window tkwin (in)

Token for window.

char *class (in)

New class name for window.


Tk_SetClass is called to associate a class with a particular window.  The class string identifies the type of the window;  all windows with the same general class of behavior (button, menu, etc.) should have the same class.  By convention all class names start with a capital letter, and there exists a Tcl command with the same name as each class (except all in lower-case) which can be used to create and manipulate windows of that class. A window's class string is initialized to NULL when the window is created.

For main windows, Tk automatically propagates the name and class to the WM_CLASS property used by window managers.  This happens either when a main window is actually created (e.g. in Tk_MakeWindowExist), or when Tk_SetClass is called, whichever occurs later.  If a main window has not been assigned a class then Tk will not set the WM_CLASS property for the window.

Tk_Class is a macro that returns the current value of tkwin's class.  The value is returned as a Tk_Uid, which may be used just like a string pointer but also has the properties of a unique identifier (see the manual entry for Tk_GetUid for details). If tkwin has not yet been given a class, then Tk_Class will return NULL.


class, unique identifier, window, window manager

Referenced By

The man page Tk_Class(3) is an alias of Tk_SetClass(3).

Tk Library Procedures