Tk_FreeXId(3tk) Tk Library Procedures Tk_FreeXId(3tk)
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NAME
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.
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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 de-
fault 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 automati-
cally calls Tk_FreeXId whenever it frees a resource, so if you use pro-
cedures 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 identi-
fier will be lost, which could cause problems if the application runs
long enough to lose all of the available identifiers.
KEYWORDS
resource identifier
Tk 4.0 Tk_FreeXId(3tk)
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