Re: [Boost-users] [iostream] Problems opening large mapped_file

7 Aug 2012

      On 2012-08-07 06:38, Vitaly Budovski wrote:
...
On 7 August 2012 02:43, Heiko Klein  wrote:
...
Hi,
I wanted to test the mapped_file_source iostream device. My code is working
well with a normal file_source device and files >= 6GB. When I change the
constructor to a mapped_file_source, it works still well for smaller files
(e.g. 150MB), but for files > 2GB I get (tested with 2.5GB):
exception occured: failed getting file size: Value too large for defined
data type
And for files > 4GB (tested with 6GB) I get:
exception occured: failed opening file: Bad file descriptor
My constructor is as follows:
using namespace boost::iostreams;
         typedef stream mmStream;
         mmStream* mmistream = new mmStream();
         mmistream->open(mapped_file_source(fileName));
I've tested against boost 1.44 and a 32bit linux (Ubuntu 10.04).
Are these general mmap problems, or am I missing some flags for
mapped_file_source?
Best regards,
Heiko
Hello,
32bit systems have only approximately 3GB of user addressable memory.
You should upgrade to a 64bit system.
Regards,
Vitaly
Vitaly,

thanks for your explanation. This makes sense for the problems with the 
6GB file. But it does not explain the 'failed getting file size: Value 
too large for defined data type' with the 2.5GB file. Do you have an 
idea why this operation fails?

Since I cannot upgrade to 64bit everywhere, I catch now the exception 
and open the stream again as file_source.

Heiko