Hi Andreas and Chet,
@Andreas: this patch seams promising. I am unable to test it now, but I will
at the beginning of next week.
@Chet: according to the specification, the retrun value of lseek is -1 if
error, or new offset from the beginning of the file if success. In my case,
the problem is that the call succeed, but r is negative due to the cast to int.
Thanks to you both,
Jean-François Gagné
________________________________
De : Chet Ramey <chet.ra...@case.edu>
À : Andreas Schwab <sch...@linux-m68k.org>
Cc : "bug-bash@gnu.org" <bug-bash@gnu.org>; "b...@packages.debian.org"
<b...@packages.debian.org>; Jean-François Gagné
<jean_francois_ga...@yahoo.com>; chet.ra...@case.edu
Envoyé le : Dimanche 4 mars 2012 23h32
Objet : Re: Bash scripting and large files: input with the read builtin from a
redirection gives unexpected result with files larger than 2GB.
On 3/4/12 3:51 PM, Andreas Schwab wrote:
> Bob Proulx <b...@proulx.com> writes:
>
>> Chet Ramey wrote:
>>> Jean-François Gagné wrote:
>>>> uname output: Linux xxxxxxxx 2.6.32-5-amd64 #1 SMP Tue Jun 14 09:42:28 UTC
>>>> 2011 x86_64 GNU/Linux
>>>> Machine Type: x86_64-pc-linux-gnu
>>>
>>> Compile and run the attached program. If it prints out `4', which it does
>>> on all of the Debian systems I've tried, file offsets are limited to 32
>>> bits, and accessing files greater than 2 GB is going to be unreliable.
>>
>> Apparently all of the Debian systems you have tried are 32-bits
>> systems. On the reporter's 64-bit amd64 system it will print out 8.
>
> But it won't help if you don't use it.
>
> diff --git a/lib/sh/zread.c b/lib/sh/zread.c
> index 0fd1199..3731a41 100644
> --- a/lib/sh/zread.c
> +++ b/lib/sh/zread.c
> @@ -161,7 +161,7 @@ zsyncfd (fd)
> int fd;
> {
> off_t off;
> - int r;
> + off_t r;
>
> off = lused - lind;
> r = 0;
That's true, and I made this change some months ago. The question is
whether or not it makes a real difference, since the only use of that
variable is to check whether the return value from lseek is -1. I
suppose under the right set of circumstances it could.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU c...@case.edu http://cnswww.cns.cwru.edu/~chet/
