Tk_FreeXId - make X resource identifier available for reuse

       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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       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.

       resource identifier

Tk                                                     4.0                                       Tk_FreeXId(3tk)

       Tk_FreeXId - make X resource identifier available for reuse

#include<tk.h>Tk_FreeXId(display,id)