Re: [gpsd-users] gpsd and shared memory

[Gary E. Miller]

Yo Roger!

On Tue, 6 Oct 2015 05:50:36 +0000
Roger Oberholtzer <address@hidden> wrote:

> Hmm.. Learned something new today.

Good.  It is a difficult subject.

> So, to reiterate a few of my questions:
> 
> 1. If the shared memory segment changes during the read, does the
> read return that there was nothing to read?

The SHMMEM RAM is always there.  So there is always something to read.

When the bookends change there is new data.
 
> 2. If the data is the same as before, does the read return it again?

The CPU can always read the SHMMEM RAM, so you alays have something to
read.

> How did I score?

The proof will be in your code.

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

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