Re: Large files on 32 and 64 bits ystem

[anon@anon.org (anon)]

With GNAT:
 
Ada.Direct_IO uses a file indexes that has the type of Count or Positive_Count. 
And these types are based on the positive range which is define as the size of a 
long_Integer which is normally in a 32-bit machine set to positive value of 
( 2**63 - 1 ).
 
So it is possible from Ada, but the interface links between Ada and the OS 
may limit the size. Or in some cases it could be the OS or device-drivers 
that is limiting the file size.

But in looking at the routine System.FileIO.Write_Buf where the exception 
occurred and the Interfaces.C.Streams they both limit the file size to 
Standard'Address_Size or in the case of GNAT 32-bit version, to a positive 
range of 32-bit word aka (2GB -1). 

So, the answer is: On a 64-bit machine is limited to 2**64-1 file size 
                     and 
                     on a 32-bit machine is limited to 2**32-1 file size.
 

In <4a1aedda$0$2855$ba620e4c@news.skynet.be>, Olivier Scalbert <olivier.scalbert@algosyn.com> writes:
>Hello everybody,
>
>Here is my weekly question ....
>
>
>I need to create a file that has 2540160000 bytes, that is a little more 
>than 2**31 bytes.
>
>On a 64 bits linux box, it is ok, but on a 32 bits linux box, I have:
>raised ADA.IO_EXCEPTIONS.DEVICE_ERROR : s-fileio.adb:1135
>
>The file length is: 2147483647, which is 2**31 - 1
>
>Is it possible to write more than 2**31 bytes with an Ada program on a 
>32 bits linux ?
>
>Thanks for your help,
>
>Olivier.