Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

  ◄Summary►  ◄Details►  ◄Example►                ◄Contents►  ◄Index►  ◄Back►
──────────────────────────────────────────────────────────────────────────────
 ON PLAY(queuemin%) GOSUB {linenumber | linelabel}
 
 Usage Notes
   ■ If your program contains event-handling statements and you are compiling
     from the BC command line, use the /W or /V option. If you do not use
     these options and your program contains event traps, Visual Basic
     generates the error message, "ON event without /V or /W on command
     line." See: ◄BC Command-Line Options►
 
   ■ The RETURN linenumber or RETURN linelabel forms of RETURN can be used to
     return to a specific line from a trapping routine. However, any GOSUB,
     WHILE, or FOR statements active at the time of the trap remain active.
     Visual Basic may generate error messages such as "NEXT without FOR."
 
   ■ A play-event trap occurs only when music is playing in the background.
     Play-event traps do not occur when music is playing in the foreground.
 
   ■ A play-event trap does not occur if the background-music queue has
     already gone from having queuemin% notes to (queuemin% - 1) notes
     when a PLAY ON is executed.
 
   ■ If queuemin% is a large number, event traps may occur often enough
     to slow down the program.
 
   ■ The ON PLAY statement specifies only the start of an event-trapping
     routine. The PLAY statement determines whether the routine is called and
     how events are handled when trapping is off. See: ◄PLAY Statement►
 
   ■ If an event occurs in a procedure, a RETURN linenumber or RETURN
     linelabel statement cannot get back into the procedure, because the
     line number or label must be in the module-level code.