Copyright (c) 1990 The Regents of the University of California.
Copyright (c) 1994-1996 Sun Microsystems, Inc.

See the file "license.terms" for information on usage and redistribution
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SCCS: @(#) GetUid.3 1.10 96/03/26 18:12:55

.so man.macros S Tk_GetUid, Tk_Uid - convert from string to unique identifier

#include <tk.h>
#typedef char *Tk_Uid
Tk_Uid
Tk_GetUid(string)
 ARGUMENTS
.AP char *string in
String for which the corresponding unique identifier is
desired.
E 
 DESCRIPTION

Tk_GetUid returns the unique identifier corresponding
to string.
Unique identifiers are similar to atoms in Lisp, and are used
in Tk to speed up comparisons and
searches. A unique identifier (type Tk_Uid) is a string pointer
and may be used anywhere that a variable of type ``char *''
could be used. However, there is guaranteed to be exactly
one unique identifier for any given string value. If Tk_GetUid
is called twice, once with string a and once with string
b, and if a and b have the same string value
(strcmp(a, b) == 0), then Tk_GetUid will return exactly
the same Tk_Uid value for each call (Tk_GetUid(a) == Tk_GetUid(b)).
This means that variables of type
Tk_Uid may be compared directly (x == y) without having to call
strcmp.
In addition, the return value from Tk_GetUid will have the
same string value as its argument (strcmp(Tk_GetUid(a), a) == 0).

 KEYWORDS
atom, unique identifier