NAME

       throw - Generate a machine-readable error

SYNOPSIS

       throw type message
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DESCRIPTION

       This  command causes the current evaluation to be unwound with an error. The error created
       is described by the type and  message  arguments:  type  must  contain  a  list  of  words
       describing  the  error  in a form that is machine-readable (and which will form the error-
       code part of the result dictionary), and message should contain text that is intended  for
       display to a human being.

       The  stack  will be unwound until the error is trapped by a suitable catch or try command.
       If it reaches the event loop without being  trapped,  it  will  be  reported  through  the
       bgerror  mechanism.  If it reaches the top level of script evaluation in tclsh, it will be
       printed on the console before, in the non-interactive case, causing an exit (the  behavior
       in other programs will depend on the details of how Tcl is embedded and used).

       By  convention,  the  words  in  the  type  argument  should  go from most general to most
       specific.

EXAMPLES

       The following produces an error that is identical to that produced by expr when trying  to
       divide a value by zero.

              throw {ARITH DIVZERO {divide by zero}} {divide by zero}

SEE ALSO

       catch(3tcl), error(3tcl), errorCode(3tcl), errorInfo(3tcl), return(3tcl), try(3tcl)

KEYWORDS

       error, exception