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Re: [Discuss-gnuradio] Windows Port Error

From: Joshua Lackey
Subject: Re: [Discuss-gnuradio] Windows Port Error
Date: Thu, 12 Jan 2006 17:05:50 -0800
User-agent: Mutt/

I don't have the GNU Radio code in front of me, so I'm not sure if this
is the problem, but MSDN says that the lpBaseAddress (the last argument)
is rounded down to a multiple of the system's memory allocation
granularity.  (Which is most likely 64k.)

Is vmcircbuf using at least 64k buffers?  Actually, it would have to be
exactly 64k (or a multiple of 64k anyway) for this to work at all.  If
the buffer is less, then the address would be rounded down to the same
address you got before.  Try setting the buffer size to 64k and

Quoting Stephane Fillod (address@hidden):
> Hi Chris,
> On Thu, Jan 12, 2006 at 11:18:30AM -0500, Robert Roberts wrote:
> > I ran test_vmcircbuf.exe  several times and each time I get the same 
> > results, shown below.
> > 
> > Testing gr_vmcircbuf_createfilemapping_factory...
> > gr_vmcircbuf_mmap_createfilemapping: non contiguous mmap 003F0000 
> > 003F0000 00010000 00400000
> Ah! looking at gnuradio-core/src/lib/runtime/gr_vmcircbuf_createfilemapping.cc
> one can see your Windows XP is trying to outsmart us!
> How can it be? Well, the code trys to make 2 (different) mappings of 
> the same offset inside paging file. It looks like the OS ignores
> the last argument of MapViewOfFileEx, which is the desired virtual
> address of the mapping. Instead of giving a brand new address (which
> could have been non-contiguous when last argument of MapViewOfFileEx 
> is ignored), the OS returns the very same virtual address of the
> first mapping, which has same offset. That's smart, but that's not 
> what we want!
> So, to sumarise, the machine has a 64-bit CPU (Opteron) with a bunch of 
> RAM (>2GB), and a 32-bit OS, Windows XP SP2. Does anyone else on the list
> encountered the same problem under Windows? More important, does anyone
> with a similar machine (Opteron+Windows XP SP2) managed to get GNU Radio
> to work?
> I have no clue on how to fix this. Can somebody help? Would someone
> familiar with Windows support forums be keen to ask why MapViewOfFileEx
> does not work as expected, and what alternative we have?
> -- 
> Stephane
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio

Joshua Lackey, PhD. -- address@hidden

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