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 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. --------------------------------- Cheap Talk? Check out Yahoo! Messenger's low PC-to-Phone call rates.