read (9 of 12 overloads)

Attempt to read a certain amount of data from a stream before returning.

template<
    typename SyncReadStream,
    typename Allocator>
std::size_t read(
    SyncReadStream & s,
    basic_streambuf< Allocator > & b);

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:

This operation is implemented in terms of zero or more calls to the stream's read_some function.

s: The stream from which the data is to be read. The type must support the SyncReadStream concept.
b: The basic_streambuf object into which the data will be read.

The number of bytes transferred.

This overload is equivalent to calling:

boost::asio::read(
    s, b,
    boost::asio::transfer_all());