Path: utzoo!mnetor!uunet!husc6!mailrus!ames!ucsd!sdcsvax!ucsdhub!hp-sdd!hplabs!hpda!hpcupt1!hpisod2!decot
From: decot@hpisod2.HP.COM (Dave Decot)
Newsgroups: comp.sys.hp
Subject: Re: time.h header files on HP9000/300.
Message-ID: <16710009@hpisod2.HP.COM>
Date: 5 May 88 00:07:11 GMT
References: <12279@sri-spam.istc.sri.com>
Organization: Hewlett Packard, Cupertino
Lines: 27

> I believe Posix defines these guys as unsigned long.  Perhaps a Posix
> guru could confirm.

The P1003.1 (POSIX kernel) draft standard does not specify high-precision time
routines such as gettimeofday() or gettimer().

Draft 2 of P1003.4 (POSIX Realtime Extension) describes a variety
of functions that refer to the following structure, defined in <sys/time.h>:

   struct timestruc {
       unsigned long tv_sec;		/* seconds */
       long tv_nsec;			/* and nanoseconds */
   };

There is currently no rationale in that document explaining why the
tv_sec type is unsigned long.

The reason we have unsigned long on HP-UX is to maximize the available
range of times for HP-UX systems.  tv_nsec does not need to be unsigned
because there are only 1 billion nanoseconds in a second.

The difference shouldn't affect anything; if you use unsigned long variables
to store values of tv_sec in your program, it will work correctly
on both HP-UX and Sun systems.

Dave Decot
hpda!decot