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.

       The -errorinfo return option of an interpreter 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 the
       -errorinfo return option.  If the info argument is present, it  is  used  to  initialize  the  -errorinfo
       return  options  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 the stack trace; in its place
       will  be info.  Historically, this feature had been 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
       When working with Tcl 8.5 or later, the following code should be used instead:
              catch {...} errMsg options
              ...
              return -options $options $errMsg

       If  the  code  argument  is  present,  then  its  value  is  stored in the -errorcode return option.  The
       -errorcode return option is intended to hold a machine-readable description of the error in  cases  where
       such  information  is available; see the return manual page for information on the proper format for this
       option's value.

EXAMPLE

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

SEE ALSO

       catch(3tcl), return(3tcl)

KEYWORDS

       error