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Diffstat (limited to 'tk/doc/GetUid.3')
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diff --git a/tk/doc/GetUid.3 b/tk/doc/GetUid.3 new file mode 100644 index 00000000000..77e896771dc --- /dev/null +++ b/tk/doc/GetUid.3 @@ -0,0 +1,50 @@ +'\" +'\" 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 +'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. +'\" +'\" RCS: @(#) $Id$ +'\" +.so man.macros +.TH Tk_GetUid 3 "" Tk "Tk Library Procedures" +.BS +.SH NAME +Tk_GetUid, Tk_Uid \- convert from string to unique identifier +.SH SYNOPSIS +.nf +\fB#include <tk.h>\fR +.sp +\fB#typedef char *Tk_Uid\fR +.sp +Tk_Uid +\fBTk_GetUid\fR(\fIstring\fR) +.SH ARGUMENTS +.AP char *string in +String for which the corresponding unique identifier is +desired. +.BE + +.SH DESCRIPTION +.PP +\fBTk_GetUid\fR returns the unique identifier corresponding +to \fIstring\fR. +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 \fBTk_GetUid\fR +is called twice, once with string \fIa\fR and once with string +\fIb\fR, and if \fIa\fR and \fIb\fR have the same string value +(strcmp(a, b) == 0), then \fBTk_GetUid\fR 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 +\fBstrcmp\fR. +In addition, the return value from \fBTk_GetUid\fR will have the +same string value as its argument (strcmp(Tk_GetUid(a), a) == 0). + +.SH KEYWORDS +atom, unique identifier |