Tk_FreeXId man page

Tk_FreeXId — make X resource identifier available for reuse

Synopsis

#include <tk.h>

Tk_FreeXId(display, id)

Arguments

Display *display (in)
Display for which id was allocated.
XID id (in)
Identifier of X resource (window, font, pixmap, cursor, graphics context, or colormap) that is no longer in use.

Description

The default allocator for resource identifiers provided by Xlib is very simple-minded and does not allow resource identifiers to be re-used. If a long-running application reaches the end of the resource id space, it will generate an X protocol error and crash. Tk replaces the default id allocator with its own allocator, which allows identifiers to be reused. In order for this to work, Tk_FreeXId must be called to tell the allocator about resources that have been freed. Tk automatically calls Tk_FreeXId whenever it frees a resource, so if you use procedures like Tk_GetFont, Tk_GetGC, and Tk_GetPixmap then you need not call Tk_FreeXId. However, if you allocate resources directly from Xlib, for example by calling XCreatePixmap, then you should call Tk_FreeXId when you call the corresponding Xlib free procedure, such as XFreePixmap. If you do not call Tk_FreeXId then the resource identifier will be lost, which could cause problems if the application runs long enough to lose all of the available identifiers.

Keywords

resource identifier

Info

4.0 Tk Tk Library Procedures