'''info default''' ''procname arg varname''

''Procname'' must be the name of a Tcl command procedure and ''arg'' must be the name of an argument to that procedure. If ''arg'' doesn't have a default value then the command returns '''0'''. Otherwise it returns '''1''' and places the default value of ''arg'' into variable ''varname''.

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See also:

   * [info]

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[Category Command] - [Tcl syntax help]