bionic (3) throw.3tcl.gz

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