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basic_stream_file::read_some (1 of 2 overloads)

Read some data from the file.

    typename MutableBufferSequence>
std::size_t read_some(
    const MutableBufferSequence & buffers);

This function is used to read data from the stream file. The function call will block until one or more bytes of data has been read successfully, or until an error occurs.



One or more buffers into which the data will be read.

Return Value

The number of bytes read.



Thrown on failure. An error code of boost::asio::error::eof indicates that the end of the file was reached.


The read_some operation may not read all of the requested number of bytes. Consider using the read function if you need to ensure that the requested amount of data is read before the blocking operation completes.


To read into a single data buffer use the buffer function as follows:

file.read_some(boost::asio::buffer(data, size));

See the buffer documentation for information on reading into multiple buffers in one go, and how to use it with arrays, boost::array or std::vector.