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.
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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