12.5.41    variable

Description:   create and initialize a namespace variable

Syntax:         variable ?name value...? name ?value?


Argument:     variable name, value


See Also:       proc, upvar, set, namespace



#example 1

namespace eval ::ezsmtp {

    global env tcl_platform

    variable mail



#example 2

SETVAL text="start1"

proc smtp_begin {s var} {

    variable mail



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 command is executed inside a Tcl procedure, it creates local variables linked to the corresponding namespace variables. In this way the variable command resembles the global command, although the global command only links to variables in the global namespace. If any values 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.