Ulrich Weigand wrote:
> Strange. Could you try running this simple test program?
> I'm able to access all of my 20Gb harddisk this way, even
> under my ancient 2.0.36 kernel ...
> off = llseek( fd, target, SEEK_SET );
I turned on compiler warnings, and not only was llseek not
defined, but the linker warned against its use and suggested
using lseek64.
> if ( count != 0x100 );
Oops, there is an extra semicolon at the end of that statement.
I modified this small program, and added some notes. I use
a command line define to force the library calls to use the
64bit variants implicitly. Program is attached. I would
suggest that we do it this way, for those files which need
64-bit access.
-Kevin
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Kevin Lawton [EMAIL PROTECTED]
MandrakeSoft, Inc. Plex86 developer
http://www.linux-mandrake.com/ http://www.plex86.org/
/* Compile the file with the following command:
*
* gcc -Wall -D_FILE_OFFSET_BITS=64 fileio64.c
*
* This compiles with off_t of size 64bits, and redirects
* IO library calls to 64bit variants. If you want to access
* the 64bit extensions directly, you can use
*
* -D_LARGEFILE64_SOURCE
*
* and then call open64(), lseek64(), etc directly.
*/
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
int main( void )
{
char buf[0x100];
int fd;
off_t off, target;
ssize_t count;
printf("sizeof(off_t) is %u bytes\n", sizeof(off_t));
target = (loff_t)(1ULL << 32);
fd = open("/dev/hda", O_RDONLY
/* I wasn't sure if you still need to pass O_LARGEFILE to
* open, even when the compile options are turning on 64-bit
* library translations? Is this needed when opening files,
* rather than filesystems?
*/
#if 0
#ifdef O_LARGEFILE
| O_LARGEFILE
#endif
#endif
);
if ( fd < 0 )
{
perror( "open" );
exit( 1 );
}
off = lseek(fd, target, SEEK_SET);
if ( off != target )
{
fprintf(stderr, "llseek FAILED: requested=0x%llx, got=0x%llx\n",
target, off);
exit( 1 );
}
fprintf(stderr, "lseek() succeeded\n");
count = read( fd, buf, 0x100 );
if ( count != 0x100 )
{
fprintf(stderr, "read FAILED: requested=%u, got=%u\n",
0x100, count);
exit( 1 );
}
fprintf(stderr, "read() succeeded\n");
fprintf(stderr, "All operations OK\n");
return 0;
}
