From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,894846be18e92713
X-Google-Attributes: gid103376,public
From: Wiljan Derks <W.Derks@nl.cis.philips.com>
Subject: Re: GNAT R/T Annex and Win95
Date: 1996/04/23
Message-ID: <317D283C.60D9@nl.cis.philips.com>#1/1
X-Deja-AN: 151065279
references: <96041916380674@psavax.pwfl.com>
 <317BC037.1CFBAE39@escmail.orl.mmc.com>
content-type: text/plain; charset=us-ascii
organization: Philips
mime-version: 1.0
newsgroups: comp.lang.ada
x-mailer: Mozilla 2.0 (WinNT; I)
Date: 1996-04-23T00:00:00+00:00
List-Id: <comp.lang.ada>

Theodore E. Dennison wrote:
> According to my NT book, there are two ways to do Timers with NT. The
> first uses the SetTimer system call. This will put a WM_TIMER event
> in the thread's normal message queue.  The resolution is ABOUT 55
> milliseconds, but there can be message queue delays. Not very useful.
> 

This remark gives the wrong impression for NT. Gnat uses things
like waitforsingleobject in its tasking implementation. For this service
one can specify a time in milliseconds, but as far as I know and any intel
system it has a resolution of 10ms.
Normally services like this one will be use for timing on NT.

> The second is the "Multimedia Timer". This timer allows you to define
> a callback that will get called directly by an interrupt, without any
> message queue processing overhead. The resolution is said to be
> "about 16 (Intel) milliseconds". Whatever that means, you can get the
> exact resolution on your system via a call to "timeGetDevCaps". (Oddly
> enough, Microsoft's example uses a resolution of 5 milliseconds) This
> is a little more useful, but still not what we would like to see.

I did not really use the multimedia timers upto now but I think one can
get resolutions upto 1 ms. I called the function timeGetDevCaps and it
reports me a minimum of 1 and a maximum of 1000000 milliseconds for
multimedia timer resolution range.

Wiljan