Re: Compatible fstat()

From: Parag Warudkar
Date: Tue Nov 08 2005 - 19:14:17 EST



On Nov 8, 2005, at 5:57 PM, Bill Davidsen wrote:

Parag Warudkar wrote:
On Nov 8, 2005, at 2:39 PM, Bob Copeland wrote:
Isn't this just because the device size is > 2**32? What if you use fseeko(3)
and #define _FILE_OFFSET_BITS 64?

Yep. I got it to return the correct hard disk size (17Gb) using lseek64 and
#define _LARGEFILE64_SOURCE
#define _FILE_OFFSET_BITS 64
Here is what I did
-------------------------------------------------
#define _LARGEFILE64_SOURCE
#define _FILE_OFFSET_BITS 64
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
int main()
{
int f;
off64_t off=0;
Why is this initialized?
f = open("/dev/hda", O_RDONLY );
if(f <= 0){
perror("open");
exit(0);
}
off = lseek64(f, 0, SEEK_SET);
Why do this? it always returns zero.
off = lseek64(f, 0, SEEK_END);
perror("llseek");
printf ("Size %lld\n", off);
close(f);
return 0;
}
RETURN VALUE
Upon successful completion, lseek returns the resulting offset
location as measured in bytes from the beginning of the file.
Otherwise, a value of (off_t)-1 is returned and errno is
set to indicate the error.


You took it a little too seriously! It was from the scribble-and- shuffle-till-it-works department ;) Sole purpose was to figure out a way to print the disk size from the device - some how that is!

But thanks for pointing out anyway - it doesn't hurt to be correct no matter what the purpose is.

Parag
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/