proc(n) 						       Tcl Built-In Commands							   proc(n)

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NAME

       proc - Create a Tcl procedure

SYNOPSIS

       proc name args body
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DESCRIPTION

       The  proc  command  creates  a  new Tcl procedure named name, replacing any existing command or procedure there may have been by that name.
       Whenever the new command is invoked, the contents of body will be executed by the Tcl interpreter.  Normally, name is unqualified (does not
       include the names of any containing namespaces), and the new procedure is created in the current namespace.  If name includes any namespace
       qualifiers, the procedure is created in the specified namespace.  Args specifies the formal arguments to the procedure.	It consists  of  a
       list, possibly empty, each of whose elements specifies one argument.  Each argument specifier is also a list with either one or two fields.
       If there is only a single field in the specifier then it is the name of the argument; if there are two fields, then the first is the  argu-
       ment name and the second is its default value.

       When  name  is  invoked	a local variable will be created for each of the formal arguments to the procedure; its value will be the value of
       corresponding argument in the invoking command or the argument's default value.	Arguments with default values need not be specified  in  a
       procedure invocation.  However, there must be enough actual arguments for all the formal arguments that don't have defaults, and there must
       not be any extra actual arguments.  There is one special case to permit procedures with variable numbers of arguments.  If the last  formal
       argument  has  the name args, then a call to the procedure may contain more actual arguments than the procedure has formals.  In this case,
       all of the actual arguments starting at the one that would be assigned to args are combined into a list (as if the list	command  had  been
       used); this combined value is assigned to the local variable args.

       When  body is being executed, variable names normally refer to local variables, which are created automatically when referenced and deleted
       when the procedure returns.  One local variable is automatically created for each of the procedure's arguments.	Global variables can  only
       be accessed by invoking the global command or the upvar command.  Namespace variables can only be accessed by invoking the variable command
       or the upvar command.

       The proc command returns an empty string.  When a procedure is invoked, the procedure's return value is the value  specified  in  a  return
       command.   If the procedure doesn't execute an explicit return, then its return value is the value of the last command executed in the pro-
       cedure's body.  If an error occurs while executing the procedure body, then the procedure-as-a-whole will return that same error.

SEE ALSO

       info(n), unknown(n)

KEYWORDS

       argument, procedure

Tcl																	   proc(n)