Tcl_UpVar(3) Tcl Library Procedures Tcl_UpVar(3)
NAME
Tcl_UpVar, Tcl_UpVar2 - link one variable to another
SYNOPSIS
#include <tcl.h>
int
Tcl_UpVar(interp, frameName, sourceName, destName, flags)
int
Tcl_UpVar2(interp, frameName, name1, name2, destName, flags)
ARGUMENTS
Interpreter containing variables; also used for error reporting.
Identifies the stack frame containing source variable. May have any of
the forms accepted by the upvar command, such as #0 or 1. Name of
source variable, in the frame given by frameName. May refer to a
scalar variable or to an array variable with a parenthesized index.
Name of destination variable, which is to be linked to source variable
so that references to destName refer to the other variable. Must not
currently exist except as an upvar-ed variable. One of
TCL_GLOBAL_ONLY, TCL_NAMESPACE_ONLY or 0; if non-zero, then destName
is a global or namespace variable; otherwise it is local to the cur-
rent procedure (or current namespace if no procedure is active). First
part of source variable's name (scalar name, or name of array without
array index). If source variable is an element of an array, gives the
index of the element. For scalar source variables, is NULL.
DESCRIPTION
Tcl_UpVar and Tcl_UpVar2 provide the same functionality as the upvar
command: they make a link from a source variable to a destination
variable, so that references to the destination are passed transpar-
ently through to the source. The name of the source variable may be
specified either as a single string such as xyx or a(24) (by calling
Tcl_UpVar) or in two parts where the array name has been separated from
the element name (by calling Tcl_UpVar2). The destination variable
name is specified in a single string; it may not be an array element.
Both procedures return either TCL_OK or TCL_ERROR, and they leave an
error message in the interpreter's result if an error occurs.
As with the upvar command, the source variable need not exist; if it
does exist, unsetting it later does not destroy the link. The destina-
tion variable may exist at the time of the call, but if so it must
exist as a linked variable.
KEYWORDS
linked variable, upvar, variable
Tcl 7.4 Tcl_UpVar(3)
UpVar 8.5.4 - Generated Thu Aug 21 09:46:14 CDT 2008