Попытка прочитать определенное количество данных в указанном смещении перед возвращением.

template<
    typename SyncRandomAccessReadDevice,
    typename MutableBufferSequence>
std::size_t read_at(
    SyncRandomAccessReadDevice & d,
    uint64_t offset,
    const MutableBufferSequence & buffers);
  » more...
template<
    typename SyncRandomAccessReadDevice,
    typename MutableBufferSequence>
std::size_t read_at(
    SyncRandomAccessReadDevice & d,
    uint64_t offset,
    const MutableBufferSequence & buffers,
    boost::system::error_code & ec);
  » more...
template<
    typename SyncRandomAccessReadDevice,
    typename MutableBufferSequence,
    typename CompletionCondition>
std::size_t read_at(
    SyncRandomAccessReadDevice & d,
    uint64_t offset,
    const MutableBufferSequence & buffers,
    CompletionCondition completion_condition);
  » more...
template<
    typename SyncRandomAccessReadDevice,
    typename MutableBufferSequence,
    typename CompletionCondition>
std::size_t read_at(
    SyncRandomAccessReadDevice & d,
    uint64_t offset,
    const MutableBufferSequence & buffers,
    CompletionCondition completion_condition,
    boost::system::error_code & ec);
  » more...
template<
    typename SyncRandomAccessReadDevice,
    typename Allocator>
std::size_t read_at(
    SyncRandomAccessReadDevice & d,
    uint64_t offset,
    basic_streambuf< Allocator > & b);
  » more...
template<
    typename SyncRandomAccessReadDevice,
    typename Allocator>
std::size_t read_at(
    SyncRandomAccessReadDevice & d,
    uint64_t offset,
    basic_streambuf< Allocator > & b,
    boost::system::error_code & ec);
  » more...
template<
    typename SyncRandomAccessReadDevice,
    typename Allocator,
    typename CompletionCondition>
std::size_t read_at(
    SyncRandomAccessReadDevice & d,
    uint64_t offset,
    basic_streambuf< Allocator > & b,
    CompletionCondition completion_condition);
  » more...
template<
    typename SyncRandomAccessReadDevice,
    typename Allocator,
    typename CompletionCondition>
std::size_t read_at(
    SyncRandomAccessReadDevice & d,
    uint64_t offset,
    basic_streambuf< Allocator > & b,
    CompletionCondition completion_condition,
    boost::system::error_code & ec);
  » more...

Requirements

Здитель: >boost/asio/read_at.hpp

Заголовок: boost/asio.hpp