async_read_at 函数是一个组合的异步操作，用于在指定的偏移量处读取一定数量的数据。
启动一个异步操作，在指定的偏移量处读取一定数量的数据。
template< typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename ReadToken = default_completion_token_t< typename AsyncRandomAccessReadDevice::executor_type>> DEDUCED async_read_at( AsyncRandomAccessReadDevice & d, uint64_t offset, const MutableBufferSequence & buffers, ReadToken && token = default_completion_token_t< typename AsyncRandomAccessReadDevice::executor_type >(), constraint_t< !is_completion_condition< ReadToken >::value > = 0); » more... template< typename AsyncRandomAccessReadDevice, typename MutableBufferSequence, typename CompletionCondition, typename ReadToken = default_completion_token_t< typename AsyncRandomAccessReadDevice::executor_type>> DEDUCED async_read_at( AsyncRandomAccessReadDevice & d, uint64_t offset, const MutableBufferSequence & buffers, CompletionCondition completion_condition, ReadToken && token = default_completion_token_t< typename AsyncRandomAccessReadDevice::executor_type >(), constraint_t< is_completion_condition< CompletionCondition >::value > = 0); » more... template< typename AsyncRandomAccessReadDevice, typename Allocator, typename ReadToken = default_completion_token_t< typename AsyncRandomAccessReadDevice::executor_type>> DEDUCED async_read_at( AsyncRandomAccessReadDevice & d, uint64_t offset, basic_streambuf< Allocator > & b, ReadToken && token = default_completion_token_t< typename AsyncRandomAccessReadDevice::executor_type >(), constraint_t< !is_completion_condition< ReadToken >::value > = 0); » more... template< typename AsyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition, typename ReadToken = default_completion_token_t< typename AsyncRandomAccessReadDevice::executor_type>> DEDUCED async_read_at( AsyncRandomAccessReadDevice & d, uint64_t offset, basic_streambuf< Allocator > & b, CompletionCondition completion_condition, ReadToken && token = default_completion_token_t< typename AsyncRandomAccessReadDevice::executor_type >(), constraint_t< is_completion_condition< CompletionCondition >::value > = 0); » more...
头文件: boost/asio/read_at.hpp
便利头文件: boost/asio.hpp
