variable(n) Tcl Built-In Commands variable(n)
variable - create and initialize a namespace variable
variable ?name value...? name ?value?
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 names-
pace. 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 locals.) 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.
global(n), namespace(n), upvar(n)
global, namespace, procedure, variable
Tcl 8.0 variable(n)