/*N SLOG_EXTRA_INTERVAL_INFOS

    Notes on the Addition of Extra Interval Description.
        This note is to clarify the usage of SLOG_PROF_XXX() routines
        especially while the user wants to add extra interval description
        to the logfile when the process of addition of interval records 
        to the logfile has been started, for instance if one needs to
        add user marker interval records.

        Also, the term interval descriptor refers to an entry in
        the Display Profile, so is the term interval information,
        abbrev. as _IntvlInfo_.  These 3 terms are used interchangably.

        Under normal circumstances, the Display Profile table is created
        by first opening the section of the logfile for storing the table
        using SLOG_PROF_Open().  Then add the interval description using
        SLOG_PROF_AddIntvlInfo() and close the table section by
        SLOG_PROF_Close().

        In the case that the logfile involves interval records whose
        interval type are NOT known until the process of inserting
        of the interval records to the logfile has been started, one 
        should open the SLOG_PROF_Open().  Then add the known record 
        definitions using SLOG_PROF_AddIntvlInfo().  However, one should
        NOT call SLOG_PROF_Close() to close the table section.  Instead,
        SLOG_PROF_SetExtraNumOfIntvlInfos() should be called to set
        the extra number of interval description entries needed( the
        number can be greater than what one actually needs ).  Then
        when user encounters a new interval record type, 
        SLOG_PROF_AddExtraIntvlInfo() can then be called to add the new
        interval record type to the Display Profile table.  This
        mechanism is very similar to that of Record Definition Table.
        Except for Record Definition Table, the above procedure has to
        be done before adding the interval record to the logfile using 
        SLOG_Irec_ToOutputStream() which does NOT allow interval
        record of with unknown interval type to the Record Definition
        table.  For Display Profile, the same procedure is implmented
        to simplify the interface for user to store interval description
        information to the logfile, the interval description information
        is NOT important till logfile needs to be displayed graphically.

.n

N*/
