"Gordon Burditt" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> >I want to be able to read a HUGE file without having such a negative
> >impact on the system's buffer cache.
[snip]
> Does O_DIRECT perhaps invoke some of the restrictions of "raw"
> device files, where the current offs
In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] wrote:
> Here's some text from my open(2) manpage:
> Transfer sizes, and the alignment of user buffer and file offset must
> all
> be multiples of the logical block size of the file system.
Does that apply in the example he gave,
Here's some text from my open(2) manpage:
Transfer sizes, and the alignment of user buffer and file offset must all
be multiples of the logical block size of the file system.
It's unlikely that in practice you can get Python's sys.stdin.read() or
os.read() to reliably use a buffer that
On Mon, 07 Nov 2005 20:42:50 +, Gordon Burditt wrote:
>> [quoted text muted]
>
> Does O_DIRECT perhaps invoke some of the restrictions of "raw"
> device files, where the current offset and transfer size must be a
> multiple of some block size? (I don't see any mention of that in
> FreeBSD's
cntl.fcntl(sys.stdin.fileno(), fcntl.F_GETFL)
>
> flags |= os.O_DIRECT
> fcntl.fcntl(sys.stdin.fileno(), fcntl.F_SETFL, flags)
> except:
> sys.stderr.write('Setting O_DIRECT on stdin attempted
> but failed\n')
>
fcntl.fcntl(sys.stdin.fileno(), fcntl.F_SETFL, flags)
except:
sys.stderr.write('Setting O_DIRECT on stdin attempted
but failed\n')
else:
sys.stderr.write('Setting O_DIRECT on stdin s
I think this is fcntl(..., F_SETFL, ...), so something like
import os, fcntl, sys
flags = fcntl.fcntl(sys.stdin.fileno(), fcntl.F_GETFL)
flags |= os.O_DIRECT
fcntl.fcntl(sys.stdin.fileno(), fcntl.F_SETFL, flags)
Jeff
pgpx52DBavw3Y.pgp
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>Is there a way of setting O_DIRECT on a preexisting file like sys.stdin?
>
>Does C allow this sort of thing?
There is no O_DIRECT or fcntl() in Standard C.
fcntl() operates on an open file descriptor, and the file descriptor
for stdin is 0. Two calls to fcntl(), one with F_GETFL and one
with F_
Is there a way of setting O_DIRECT on a preexisting file like sys.stdin?
Does C allow this sort of thing?
Thanks!
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