Re: Large File Support

On 16.11.2005, at 11:36, Wilfried Goesgens wrote:

> On Tue, Nov 15, 2005 at 04:03:30PM +0100, Andreas Fink wrote:
>> As a side note:
>>
>> Kannel (to be exact gwlib) on MacOS X does not seem to run into  
>> the  2GB barrier as it does on Linux.
> which is a 64-bit architecture?

MacOS X is a 32bit architecture kernel on a 64bit memory space and  
with 64bit operations available since a long long time.
You can compile 64bit applications on MacOS X but all the gui  
environment is 32bit and will stay like this. There's no real benefit  
of having it compiled in 64bit if you use a PowerPC G5 cpu. So unless  
you really need to address more than 4GB of memory, there's no point  
switching to 64bits on the application side. What I'm trying to say  
here is that kannel was compiled out of the box without any -arch  
ppc64 flags being passed and the file size dont have those problems.  
The odd on the Linux size is that the problem once was that files  
actually couldnt grow over 2GB or 4GB but todays kernels and  
filesystem has no problem having files growing larger than 4GB but  
kannel still has problems writing after 4GB. This limitation has  
never existed under MacOS X.

(Read http://developer.apple.com/documentation/Darwin/Conceptual/ 
64bitPorting/index.html for a few interesting facts about why 64bit  
or why not)

Probably the problem (under linux) comes from some wrong typecast  
assuming size_t/pos_t/off_t/pointer to be the same as int or 32bit  
which is not the case.


Andreas Fink
Fink Consulting GmbH

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