id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
12383,boost::asio fails to read more than 65536 bytes from file asyncronously,AStepanjuk@…,chris_kohlhoff,"When more than `65536` bytes are read into a buffer from a file using `boost::asio::windows::stream_handle` asynchronously, then buffer contains the wrong data after reading is completed.

Starting from `65537`th byte the buffer contains the the data from the very beginning of the file, rather than the expected data.

Here is a code example, which reproduces the issue:

{{{
auto handle = ::CreateFile(L""BigFile.xml"", GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, nullptr);
boost::asio::io_service ios;

boost::asio::windows::stream_handle streamHandle(ios, handle);

const auto to_read_bytes = 100000;
char buffer[to_read_bytes];

boost::asio::async_read(streamHandle, boost::asio::buffer(buffer, to_read_bytes), [](auto &ec, auto read) {
	std::cout << ""Bytes read: "" << read << std::endl;
});

ios.run();

auto bufferBegin = std::string(buffer, 38);
auto bufferCorrupted = std::string(buffer + 65536, 38);   // <- it contains bytes from the beginning of the file

std::cout << ""offset 0: "" << bufferBegin << std::endl;
std::cout << ""offset 65536: "" << bufferCorrupted << std::endl;   

::CloseHandle(handle);
}}}

That code produces an output:

    > `Bytes read: 100000` [[br]]
    > `offset 0: <?xml version=""1.0"" encoding=""UTF-8""?>`  [[br]]
    > `offset 65536: <?xml version=""1.0"" encoding=""UTF-8""?>` [[br]]

The source file is a valid XML file, which is bigger than 65536 bytes in size.

This is reproducible with boost 1.61 + VS2015. Also that issue was in boost 1.55 + VS2010.  [[br]]
Operating systems are: Windows 7 and Windows Server 2008R2.",Bugs,new,To Be Determined,asio,Boost 1.61.0,Problem,,,