Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Contact Us
Online Help
Domain Status
Man Pages

Virtual Servers

Topology Map

Server Agreement
Year 2038

USA Flag



Man Pages

Manual Reference Pages  -  TCL_UPVAR (3)


Tcl_UpVar, Tcl_UpVar2 - link one variable to another




#include <tcl.h>

int Tcl_UpVar(interp, frameName, sourceName, destName, flags)

int Tcl_UpVar2(interp, frameName, name1, name2, destName, flags)


.TP 15 Tcl_Interp *interp (in)
Tcl_Interp*interp Tcl_Interp Interpreter containing variables; also used for error reporting.
.TP 15 const char *frameName (in)
const char*frameName const char Identifies the stack frame containing source variable. May have any of the forms accepted by the upvar command, such as #0 or 1.
.TP 15 const char *sourceName (in)
const char*sourceName const char 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.
.TP 15 const char *destName (in)
const char*destName const char 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.
.TP 15 int flags (in)
int       flags int 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 current procedure (or current namespace if no procedure is active).
.TP 15 const char *name1 (in)
const char*name1 const char First part of source variable’s name (scalar name, or name of array without array index).
.TP 15 const char *name2 (in)
const char*name2 const char If source variable is an element of an array, gives the index of the element. For scalar source variables, is NULL.





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 transparently 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 destination variable may exist at the time of the call, but if so it must exist as a linked variable.


linked variable, upvar, variable
Search for    or go to Top of page |  Section 3 |  Main Index

Tcl TCL_UPVAR (3) 7.4

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.