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error(n)                                    Tcl Built-In Commands                                   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 informa-tion information
       tion is available; see the tclvars manual page 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.


SEE ALSO
       catch(n), tclvars(n)


KEYWORDS
       error, errorCode, errorInfo



Tcl                                                                                                 error(n)