[Boost-users] mapped_file_source

From: Victor Morales-Duarte (victor_moralesduarte_at_[hidden])
Date: 2006-12-14 12:13:39

Hi all,

I'm trying to use boost::iostream::mapped_file_source directly, but I can't close and then re-open the file without getting an exception. Here is an example.

**********************************************************************************************

#include <boost/iostreams/device/mapped_file.hpp>

int main( void )
{
    std::string fileName( "SomeFile.ext" );
    int osAlignment = boost::iostreams::mapped_file_source::alignment();

   boost::iostreams::mapped_file_source fileMap( fileName, 2 * osAlignment, 0 );

   // Load data to application memory using fileMap.data();

   fileMap.close();

   // The following line throws because fileMap.is_open() returns true
   fileMap.open( fileName, 1024 * osAlignment, 1024 * osAlignment );

   // Load more data to application memory using fileMap.data();
 
   return 0;
}

*****************************************************************************************
What I truly don't understand is why a call to is_open() woud return true immediately after a call to close(). What do I need to do to be able to map
different parts of the same file? I can't map the whole file because the number
of files that I need to process is large enough that I'd run out of allocation
space for my process.

Thanks guys.

Victor

I'm using boost 1.33.1 with Visual Studio 2003 on WinXP SP2.

 
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