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A completion token type that causes an asynchronous operation to return a future.
template< typename Allocator = std::allocator<void>> class use_future_t
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Description |
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The allocator type. The allocator is used when constructing the std::promise object for a given asynchronous operation. |
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Name |
Description |
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Obtain allocator. |
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Wrap a function object in a packaged task. |
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(Deprecated: Use rebind().) Specify an alternate allocator. |
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Specify an alternate allocator. |
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use_future_t [constructor] |
Construct using default-constructed allocator. |
The use_future_t
class is a completion token type that is used to indicate that an asynchronous
operation should return a std::future object. A use_future_t object may be passed
as a completion token to an asynchronous operation, typically using the special
value asio::use_future. For example:
std::future<std::size_t> my_future = my_socket.async_read_some(my_buffer, asio::use_future);
The initiating function (async_read_some in the above example) returns a future that will receive the result of the operation. If the operation completes with an error_code indicating failure, it is converted into a system_error and passed back to the caller via the future.
Header: asio/use_future.hpp
Convenience header: asio.hpp