Tcl Built-In Commands                                   error(1T)





NAME
     error - Generate an error

SYNOPSIS
     error message ?info? ?code?



DESCRIPTION
     Returns a TCLEROR code, which causes  command  interpreta-
     tion 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 con-
     taining the error command will not appear in  errorInfo;  in
     its place will be info.  This feature is most useful in con-
     junction 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 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.

EXAMPLE
     Generate an error if a basic mathematical operation fails:
          if {1]2 != 3} {
              error "something is very wrong with addition"
          }


SEE ALSO
     catch(1T), return(1T), tclvars(1T)



Tcl                       Last change:                          1






Tcl Built-In Commands                                   error(1T)



KEYWORDS
     error, errorCode, errorInfo

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     
       ATRIBUTE TYPE     ATRIBUTE VALUE
    
     Availability         SUNWTcl        
    
     Interface Stability  Uncommitted    
    

NOTES
     Source for Tcl is available on http:/opensolaris.org.






































Tcl                       Last change:                          2