VS_FLock()           Locks the currently selected database

Description:

  VS_FLock() locks the currently selected database file or notifies the
  user if unsuccessful.

Syntax:     

  l_Success = VS_FLock()

Pass:       

  Nothing

Return:     

  l_Success is a logical expression that will be set to .T. if
  successful, otherwise .F.

Notes:      


Example:    

  BEGIN SEQUENCE

     IF .NOT. VS_FLOCK()
        ac_msg[1] = "Unable to lock current file"
        ac_msg[2] = "Operation aborted"
        VS_MSG(ac_msg,2,"","")
        INKEY(5)
        BREAK
     ENDIF
     ...

  END SEQUENCE

Usage:      

  VS_FLock() will try to lock the currently selected database file.  If
  it is unsuccessful, a non-screen destructive message stating "Waiting
  for busy network. Press any key to abort." will appear on the screen
  and VS_FLock() will continue attempting to lock the currently selected
  database file.  If the user aborts the operation by pressing a key,
  VS_FLock() will return a logical value of false.  If VS_FLock()
  returns a value of false, it is your job as the programmer to abort
  the operation and recover properly.