Re: Compatible fstat()

[Parag Warudkar <kernel-stuff@comcast.net>]

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