Attempt to read a certain amount of data from a stream before returning.
template< typename SyncReadStream, typename MutableBufferSequence> std::size_t read( SyncReadStream & s, const MutableBufferSequence & buffers);
This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:
- The supplied buffers are full. That is, the bytes transferred is equal to the sum of the buffer sizes.
- An error occurred.
This operation is implemented in terms of one or more calls to the stream's read_some function.
Parameters
- s
The stream from which the data is to be read. The type must support the SyncReadStream concept.
- buffers
One or more buffers into which the data will be read. The sum of the buffer sizes indicates the maximum number of bytes to read from the stream.
Return Value
The number of bytes transferred.
Exceptions
- boost::system::system_error
Thrown on failure.
Example
To read into a single data buffer use the buffer function as follows:
boost::asio::read(s, 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.
Remarks
This overload is equivalent to calling:
boost::asio::read( s, buffers, boost::asio::transfer_all());