Re: Timers

From:

"Tom Serface" <tom@camaswood.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Wed, 19 Aug 2009 08:19:03 -0700

Message-ID:

<DF6BE018-E58A-46BB-AD79-D72A3664939C@microsoft.com>

I agree with others that a timer would be a good solution for this one. The
only hesitation I would have is if you are implementing multiple instances
of the edit control you may end up with a lot of timers, but you'd have to
work hard to make this a problem. In any event, implementing with a timer
would be really easy to encapsulate and try out to see if, in practice, it
does what you want. It also makes the control more self contained.

Tom

"vvf" <vvf@vvf.com> wrote in message
news:OuZgTHLIKHA.4708@TK2MSFTNGP03.phx.gbl...

Hi All,

I am trying to implement a mechanism that would allow me to perform an
action every 1 second. As an exercise, I am implementing an "edit box"
from scratch (including text drawing, etc) and now I need to make the
cursor blink.

Here is what I thought of:

1) WM_TIMER. This is out of the question. It's not reliable for obvious
reasons (message queue may have lots of messages before WM_TIMER)

2) Have a thread that does a WFSO on an object with a timeout of 1000 ms
but, wouldn't this WFSO be the same as a Sleep(1000) ? Since Windows is
not a real time operating system, I know I can't have precisions less than
55ms or 15 or 10ms on some OSes, but would I be OK with Sleep(1000) ? I
think I should be and besides, let's be reasonsable, since this is a
blinking cursor, +/- some milliseconds won't make a difference to the
human eye.

3) Use multi-media timers. These are using threads internally so would it
be better to just implement my 2nd method shown above ? Would I have any
advantages using multi-media timers over the 2nd method ? Are these timers
accurate?

Are there any better solutions to my problem ?

Thank you for clarifying these things for me.

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