Tk_GetUid(3) Tk Library Procedures Tk_GetUid(3) ______________________________________________________________________________ NAME Tk_GetUid, Tk_Uid - convert from string(3,n) to unique identifier SYNOPSIS #include <tk.h> Tk_Uid Tk_GetUid(string(3,n)) ARGUMENTS char *string(3,n) (in(1,8)) String for which the corre- sponding unique identifier is desired. _________________________________________________________________ DESCRIPTION Tk_GetUid returns the unique identifier corresponding to string(3,n). Unique identifiers are similar to atoms in(1,8) Lisp, and are used in(1,8) Tk to speed up comparisons and searches. A unique identifier (type Tk_Uid) is a string(3,n) 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(3,n) value. If Tk_GetUid is called twice, once with string(3,n) a and once with string(3,n) b, and if(3,n) a and b have the same string(3,n) 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 com- pared directly (x == y) without having to call strcmp. In addition, the return value from Tk_GetUid will have the same string(3,n) value as its argument (strcmp(Tk_GetUid(a), a) == 0). KEYWORDS atom, unique identifier Tk Tk_GetUid(3)