Tk_GetUid(3) Tk Tk_GetUid(3)
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NAME
Tk_GetUid, Tk_Uid - convert from string to unique identifier
SYNOPSIS
#include <tk.h>
#typedef char *Tk_Uid
Tk_Uid
Tk_GetUid(string)
ARGUMENTS
char *string (in) String for which
the corresponding
unique identifier
is desired.
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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
Page 1 (printed 2/26/99)
