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unknown(1tcl)
unknown -- handle attempts to use non-existent commands
Synopsis
unknown
cmdName
[
arg arg ...
]
Description
This command is not a core part of Tcl, but Tcl will invoke it if it does exist (that is, if a function called
unknown
has been written and linked to Tcl in the current application). If the Tcl interpreter encounters a command name for which there is not a defined command, then Tcl checks for the existence of a command named
unknown
. If there is no such command, then the interpreter returns an error. If the
unknown
command exists, then it is invoked with arguments consisting of the fully-substituted name and arguments for the original non-existent command. The
unknown
command typically does things like searching through library directories for a command procedure with the name
cmdName
, or expanding abbreviated command names to full-length, or automatically executing unknown commands as sub-processes. In some cases (such as expanding abbreviations)
unknown
will change the original command slightly and then (re-)execute it. The result of the
unknown
command is used as the result for the original non-existent command.
25 April 2004
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004