The async_read_at function is a composed asynchronous operation that reads a certain amount of data at the specified offset.

Start an asynchronous operation to read a certain amount of data at the specified offset.

template<
    typename AsyncRandomAccessReadDevice,
    typename MutableBufferSequence,
    typename ReadHandler = DEFAULT>
DEDUCED async_read_at(
    AsyncRandomAccessReadDevice & d,
    uint64_t offset,
    const MutableBufferSequence & buffers,
    ReadHandler && handler = DEFAULT);
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template<
    typename AsyncRandomAccessReadDevice,
    typename MutableBufferSequence,
    typename CompletionCondition,
    typename ReadHandler = DEFAULT>
DEDUCED async_read_at(
    AsyncRandomAccessReadDevice & d,
    uint64_t offset,
    const MutableBufferSequence & buffers,
    CompletionCondition completion_condition,
    ReadHandler && handler = DEFAULT);
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template<
    typename AsyncRandomAccessReadDevice,
    typename Allocator,
    typename ReadHandler = DEFAULT>
DEDUCED async_read_at(
    AsyncRandomAccessReadDevice & d,
    uint64_t offset,
    basic_streambuf< Allocator > & b,
    ReadHandler && handler = DEFAULT);
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template<
    typename AsyncRandomAccessReadDevice,
    typename Allocator,
    typename CompletionCondition,
    typename ReadHandler = DEFAULT>
DEDUCED async_read_at(
    AsyncRandomAccessReadDevice & d,
    uint64_t offset,
    basic_streambuf< Allocator > & b,
    CompletionCondition completion_condition,
    ReadHandler && handler = DEFAULT);
  » more...

Requirements

Header: boost/asio/read_at.hpp

Convenience header: boost/asio.hpp