tcl7.6 User Commands - catch






NAME

     catch - Evaluate script and trap exceptional returns


SYNOPSIS

     catch script ?varName?





DESCRIPTION

     The catch command may be used to prevent errors from  abort-
     ing command interpretation.  Catch calls the Tcl interpreter
     recursively to execute script, and always returns  a  TCL_OK
     code,  regardless  of any errors that might occur while exe-
     cuting script.  The return value from  catch  is  a  decimal
     string giving the code returned by the Tcl interpreter after
     executing script.  This will be 0 (TCL_OK) if there were  no
     errors  in  script;  otherwise it will have a non-zero value
     corresponding to one of the exceptional  return  codes  (see
     tcl.h  for  the definitions of code values).  If the varName
     argument is given, then it gives the  name  of  a  variable;
     catch  will  set  the  variable  to the string returned from
     script (either a result or an error message).

     Note that catch catches all exceptions, including those gen-
     erated by break and continue as well as errors.



KEYWORDS

     catch, error