Easiest Example for upvar in TCL

Usage:

Used when we have to change the value of a global variable from inside a procedure’s scope

Example

proc example {one two} {

upvar $one local1

upvar $two local2

set local1 Kavitha

set local2 Anbarasu

}

set glob1 David

set glob2 Beckam

puts $glob1

puts $glob2\n

example glob1 glob2

puts $glob1

puts $glob2

Output

David
Beckam

Kavitha
Anbarasu

In the above example we are able to change the value of two global variables glob1 and glob2 from within a procedure