Re: POSIX.Memory_Mapping.Map_Memory

From: Adrian Hoe (byhoe_at_greenlime.com)
Date: 02/27/05 

Date: 26 Feb 2005 22:59:30 -0800

Florian Weimer wrote:
> * Mark Lorenzen:
>
> >> I was just wondering: Is it allowed to map a device file as shared
> >> memory? Try to use MAP_PRIVATE instead of MAP_SHARED.
> >
> > Furthermore: I do not think that it is possible to map character
> > special files, since it only allows sequential access. You can
> > probably only map block special files.
>
> It's possible to map /dev/zero. In fact, there is little difference
> between character and block devices these days.

Just for the purpose of recording for people who may need this in the
future:

I've successfully mapped the memory with
POSIX.Memory_Mapping.Map_Memory.

The VIDIOCGMBUF ioctl has to be issued before Map_Memory. This ioctl
reports the size of buffer to Memory_Map and the offset within the
buffer for each frame.

My application is far from completion but I have resolved this
Memory_Map issue. I believe the wheel has just started rolling again.
:-)

Regards, 

--
Adrian Hoe