---
name: "variable"
section: "n"
platform: "macos"
package: "tcl"
version: "152"
release: "macOS 26.5"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/variable/n"
---

# variable(n)

create and initialize a namespace variable

## NAME

variable - create and initialize a namespace variable

## SYNOPSIS

**variable** ?*name value...*? *name* ?*value*?

## DESCRIPTION

This command is normally used within a **namespace eval** command to create one or more variables within a namespace. Each variable *name* is initialized with *value*. The *value* for the last variable is optional.

If a variable *name* does not exist, it is created. In this case, if *value* is specified, it is assigned to the newly created variable. If no *value* is specified, the new variable is left undefined. If the variable already exists, it is set to *value* if *value* is specified or left unchanged if no *value* is given. Normally, *name* is unqualified (does not include the names of any containing namespaces), and the variable is created in the current namespace. If *name* includes any namespace qualifiers, the variable is created in the specified namespace.  If the variable is not defined, it will be visible to the **namespace which** command, but not to the **info exists** command.

If the **variable** command is executed inside a Tcl procedure, it creates local variables linked to the corresponding namespace variables (and therefore these variables are listed by **info vars**.) In this way the **variable** command resembles the **global** command, although the **global** command only links to variables in the global namespace. If any *value*s are given, they are used to modify the values of the associated namespace variables. If a namespace variable does not exist, it is created and optionally initialized.

A *name* argument cannot reference an element within an array. Instead, *name* should reference the entire array, and the initialization *value* should be left off. After the variable has been declared, elements within the array can be set using ordinary **set** or **array** commands.

## EXAMPLES

Create a variable in a namespace: namespace eval foo {\
     **variable** bar 12345 }

Create an array in a namespace: namespace eval someNS {\
     **variable** someAry\
     array set someAry {\
         someName  someValue\
         otherName otherValue\
     } }

Access variables in namespaces from a procedure: namespace eval foo {\
     proc spong {} {\
         \# Variable in this namespace\
         **variable** bar\
         puts "bar is $bar"

        \# Variable in another namespace\
         **variable** ::someNS::someAry\
         parray someAry\
     } }

## SEE ALSO

[global(n)](/global/n.md), [namespace(n)](/namespace/n.md), [upvar(n)](/upvar/n.md)

## KEYWORDS

global, namespace, procedure, variable