error(n)                     Tcl ( )                     error(n)



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     NAME
          error - Generate an error

     SYNOPSIS
          error message ?info? ?code?
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     DESCRIPTION
          Returns   a   TCL_ERROR   code,   which    causes    command
          interpretation  to  be unwound.  Message is a string that is
          returned to the application to indicate what went wrong.

          If the info argument is provided and  is  non-empty,  it  is
          used to initialize the global variable errorInfo.  errorInfo
          is used to accumulate a stack trace of what was in  progress
          when  an  error occurred; as nested commands unwind, the Tcl
          interpreter adds information  to  errorInfo.   If  the  info
          argument  is present, it is used to initialize errorInfo and
          the first increment of unwind information will not be  added
          by  the  Tcl  interpreter.   In  other  words,  the  command
          containing the error command will not appear  in  errorInfo;
          in  its  place will be info.  This feature is most useful in
          conjunction with the  catch  command:   if  a  caught  error
          cannot be handled successfully, info can be used to return a
          stack trace reflecting the original point of  occurrence  of
          the error:

               catch {...} errMsg
               set savedInfo $errorInfo
               ...
               error $errMsg $savedInfo

          If the code argument is present, then its value is stored in
          the errorCode global variable.  This variable is intended to
          hold a machine-readable description of the  error  in  cases
          where  such information is available; see the section BUILT-
          IN VARIABLES below for information on the proper format  for
          the  variable.   If  the  code argument is not present, then
          errorCode is automatically reset  to  ``NONE''  by  the  Tcl
          interpreter as part of processing the error generated by the
          command.


     KEYWORDS
          error, errorCode, errorInfo







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