From: Mark Lorenzen <mark.lorenzen@ofir.dk>
Subject: Re: POSIX.Memory_Mapping.Map_Memory
Date: 30 Jan 2005 17:36:48 +0100
Date: 2005-01-30T17:36:48+01:00 [thread overview]
Message-ID: <m3fz0ic1r3.fsf@0x5358c0df.boanxx18.adsl-dhcp.tele.dk> (raw)
In-Reply-To: m3oef6c2ke.fsf@0x5358c0df.boanxx18.adsl-dhcp.tele.dk
Mark Lorenzen <mark.lorenzen@ofir.dk> writes:
> "Adrian Hoe" <byhoe@greenlime.com> writes:
>
> > Mark Lorenzen wrote:
> > >
> > > I corrected the above mentioned problem and successfully opened and
> > > mapped a file. Strange.
> >
> > Yes. I made a mistake. It should be:
> >
> > if (buf == MAP_FAILED)
> >
> > and it gave me error as well. And the strace says:
> >
> > open("/dev/video0", O_RDWR) = 3
> > mmap2(NULL, 230400, PROT_READ|PROT_WRITE, MAP_SHARED, 3, 0) = -1 EINVAL
>
> 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.
>
> > (Invalid argument)
> > fstat64(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
> > m
> >
> > mmap gives EINVAL in my C and Ada programs.
> > --
> > Adrian Hoe
>
> - Mark Lorenzen
next prev parent reply other threads:[~2005-01-30 16:36 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-29 15:58 POSIX.Memory_Mapping.Map_Memory Adrian Hoe
2005-01-29 16:20 ` POSIX.Memory_Mapping.Map_Memory Mark Lorenzen
2005-01-29 16:31 ` POSIX.Memory_Mapping.Map_Memory Adrian Hoe
2005-01-29 18:44 ` POSIX.Memory_Mapping.Map_Memory Mark Lorenzen
2005-01-30 2:45 ` POSIX.Memory_Mapping.Map_Memory Adrian Hoe
2005-01-30 2:48 ` POSIX.Memory_Mapping.Map_Memory Adrian Hoe
2005-01-30 15:39 ` POSIX.Memory_Mapping.Map_Memory Mark Lorenzen
2005-01-30 16:02 ` POSIX.Memory_Mapping.Map_Memory Adrian Hoe
2005-01-30 16:19 ` POSIX.Memory_Mapping.Map_Memory Mark Lorenzen
2005-01-30 16:36 ` Mark Lorenzen [this message]
2005-01-30 18:51 ` POSIX.Memory_Mapping.Map_Memory Florian Weimer
2005-02-27 6:59 ` POSIX.Memory_Mapping.Map_Memory Adrian Hoe
2005-02-27 13:03 ` POSIX.Memory_Mapping.Map_Memory Mark Lorenzen
2005-01-30 16:05 ` POSIX.Memory_Mapping.Map_Memory Adrian Hoe
2005-01-30 16:22 ` POSIX.Memory_Mapping.Map_Memory Mark Lorenzen
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