qck.hlp (Table of Contents; Topic list)
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Error/Event Trapping Summary
  Summary                                      Contents  Index  Back
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 Error/Event Trapping Summary
 
 ■ Visual Basic provides several functions and statements that allow you to:
    • Trap errors or events while a program is running
    • Get error-status data
    • Define your own error codes
 
 ■ The following keywords are used in Visual Basic to perform error- and
   event-trapping tasks. With the exception of ON KEY and KEY ON, these
   event statements can also be used with object-specific events.
   See: Object Events Summary
 
   COM Statement            Controls trapping of COM port events
   ERDEV Function           Returns error code from device
   ERDEV$ Function          Returns device name that generated error
   ERL Function             Returns line number where error occurred
   ERR Function             Returns the most recent run-time error code
   ERR Statement            Assigns integer value to ERR
   ERROR Statement          Simulates occurrence of an error
   ERROR$ Function          Returns error message for specified error code
   EVENT Statement          Enables/disables event trapping
   GOSUB...RETURN Statement Branches to and returns from a subroutine
   KEY Statement            Controls trapping of defined KEY events
   LOCAL Keyword            Indicates local error-handling routine
   OFF Keyword              Disables event trapping with event statements
   ON Keyword               Enables event trapping/specifies events to trap
   ON COM Statement         Branches to routine on defined COM event
   ON ERROR Statement       Enables error handling during program execution
   ON KEY Statement         Branches to routine on defined KEY event
   ON PEN Statement         Branches to routine on defined PEN event
   ON PLAY Statement        Branches to routine when less than queuemin%
   ON STRIG Statement       Branches to routine on defined STRIG event
   ON TIMER Statement       Branches to routine on defined TIMER event
   ON UEVENT Statement      Defines event handler for user-defined event
   PEN Statement            Controls trapping of defined PEN events
   PLAY Statement           Controls trapping of defined PLAY events
   RESUME Statement         Resumes program execution after error handling
   SetUEvent Routine        Sets entry point for user-defined event
   STRIG Statement          Controls trapping of defined STRIG events
   TIMER Statement          Controls trapping of defined TIMER events
   UEVENT Statement         Controls trapping of user-defined events
 
 See: Keywords by Task  Run-Time Error Codes