Timestamp field

[bvining@xxxxxxxxxxxx]

>
>I would not depend on using the timestamp as a unique key.  As you have
>found out, on a sufficiently fast enough machine you can get duplicates.
>The upshot of this is that even if it works today, when the next generation
>of CPUs come out it might fail.
>

Just wanted to point out that there is a unique timestamp available
on the system.  If you access the system Time of Day (TOD) clock then
the full 8-byte value will be unique.  This uniqueness is ensured by
the system so long as you do not set the system time backwards (which
means there currently is a small exposure for those systems that
observe Daylight Saving Time/Standard Time).  To access the TOD in RPG
use:

DMatTOD           PR                  EXTPROC('_MATTOD')
D                                8
DReceiver         s              8
C                   callp     MatTOD(Receiver)

Receiver can then be converted to a more readable format using the
Convert Date and Time (QWCCVTDT) API and format *DTS.  The *DTS format
itself measures time with 8-microsecond granularity, and uses bits beyond
bit 48 (base 0) to provide unique values for when multiple accesses to
the TOD may occur within the same 8-microsecond interval.

Bruce Vining



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