source: downloads/tcl8.5.2/doc/global.n @ 42

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'\" Copyright (c) 1994-1997 Sun Microsystems, Inc.
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'\" RCS: @(#) $Id: global.n,v 1.12 2007/12/13 15:22:32 dgp Exp $
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.so man.macros
.TH global n "" Tcl "Tcl Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
global \- Access global variables
.SH SYNOPSIS
\fBglobal \fIvarname \fR?\fIvarname ...\fR?
.BE

.SH DESCRIPTION
.PP
This command has no effect unless executed in the context of a proc body.
If the \fBglobal\fR command is executed in the context of a proc body, it
creates local variables linked to the corresponding global variables (and
therefore these variables are listed by info locals).
.PP
If \fIvarname\fR contains namespace qualifiers, the local variable's name is
the unqualified name of the global variable, as determined by the
\fBnamespace tail\fR command. 
.PP
\fIvarname\fR is always treated as the name of a variable, not an
array element.  An error is returned if the name looks like an array element,
such as \fBa(b)\fR.
.SH EXAMPLES
This procedure sets the namespace variable \fI::a::x\fR
.CS
proc reset {} {
    \fBglobal\fR a::x
    set x 0
}
.CE
.PP
This procedure accumulates the strings passed to it in a global
buffer, separated by newlines.  It is useful for situations when you
want to build a message piece-by-piece (as if with \fBputs\fR) but
send that full message in a single piece (e.g. over a connection
opened with \fBsocket\fR or as part of a counted HTTP response).
.CS
proc accum {string} {
    \fBglobal\fR accumulator
    append accumulator $string \en
}
.CE

.SH "SEE ALSO"
namespace(n), upvar(n), variable(n)

.SH KEYWORDS
global, namespace, procedure, variable