Tk_GetUid(3)                 Tk Library Procedures                Tk_GetUid(3)

______________________________________________________________________________

NAME
       Tk_GetUid, Tk_Uid - convert from string to unique identifier

SYNOPSIS
       #include <tk.h>

       Tk_Uid
       Tk_GetUid(string)

ARGUMENTS
       char *string (in)                         String for which the
                                                 corresponding unique
                                                 identifier is desired.
______________________________________________________________________________

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

Tk                                                                Tk_GetUid(3)