Sub-optimal libc's read-ahead buffering behaviour
ache at FreeBSD.ORG
Thu Aug 4 06:39:14 GMT 2005
On Thu, Aug 04, 2005 at 10:02:51AM +0400, Andrey Chernov wrote:
> But between read & seek character device itself can move its pointer in
Well, this phrase is incorrectly constructed. I mean: by reading
from the character device, the pointer can be moved to same unpredictable
places, say, become negative, or other overflow happens.
So (considering changing content like /dev/mem too), any buferization is
potentially dangerous here. fseek traditionally used as buferization
break, in case, say, between fread and fwrite. In case SEEK_CUR still uses
the buffer, it probably should not for character device.
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