Re: [boost] [filesystem] revised function to determine available filesystem space

From: Beman Dawes (bdawes_at_[hidden])
Date: 2005-09-13 06:46:05

"Kevin Wheatley" <hxpro_at_[hidden]> wrote in message 
news:43269DAA.3667BE36_at_cinesite.co.uk...
> Beman Dawes wrote:
>> How safe is the assumption that uintmax_t is large enough nowadays for 
>> any
>> modern compiler on a system supporting large disks.
>
> Under IRIX, you would use statfs() to get the free space from a path,
> that returns a structure composed of 2 relavent parts both are of type
> long:
>
>          long    f_bsize;    /* Block size */
>          long    f_bfree;    /* Count of free blocks */
>
> where a long may be either 32 or 64 bits wide... but an unsigend int
> is only 32 bits so your assumption doesn't hold more than 4GB as a
> byte count ... which in my business is not enough (~50 MB per frame 24
> frames per second, 60 seconds per minute... 2-3 hours per finished
> film, 10 times that for raw footage, even at 1/2 resolution its
> ~12MB/frame).
>
> So I'd favour something a little larger... ssize_t keeps pace with the
> size of a long

For all practical purposes, uintmax_t is 64-bits, so that should be enough.

> Our largest single volume is above 6TB, admittedly our *free* space is
> never that large :-)

Don't we wish:-)

Thanks,

--Beman