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

From: Kevin Wheatley (hxpro_at_[hidden])
Date: 2005-09-13 04:36:42

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

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

Kevin

-- 
| Kevin Wheatley, Cinesite (Europe) Ltd | Nobody thinks this      |
| Senior Technology                     | My employer for certain |
| And Network Systems Architect         | Not even myself         |