IsSound()

         Determines if speaker sounds are allowed

    Syntax:

         IsSound( [lMode] ) -> lOldMode

         lMode : A logic to indicate the new value.

    Description:

         This function determines if speaker sounds are allowed when
         a function of Fast Library is running.

    Return:

         Actual mode.

    Example:

         lSound := IsSound( .F. )
         Serpent()                      // without sound
         IsSound( lSound )