80 lines
1.5 KiB
Plaintext
80 lines
1.5 KiB
Plaintext
[/
|
|
/ Copyright (c) 2003-2023 Christopher M. Kohlhoff (chris at kohlhoff dot com)
|
|
/
|
|
/ Distributed under the Boost Software License, Version 1.0. (See accompanying
|
|
/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
|
/]
|
|
|
|
[section:NullaryToken Nullary token requirements]
|
|
|
|
A nullary token is a [link boost_asio.overview.model.completion_tokens completion
|
|
token] for completion signature `void()`.
|
|
|
|
[heading Examples]
|
|
|
|
A free function as a nullary token:
|
|
|
|
void nullary_handler()
|
|
{
|
|
...
|
|
}
|
|
|
|
A nullary token function object:
|
|
|
|
struct nullary_handler
|
|
{
|
|
...
|
|
void operator()()
|
|
{
|
|
...
|
|
}
|
|
...
|
|
};
|
|
|
|
A lambda as a nullary token:
|
|
|
|
boost::asio::post(...,
|
|
[]()
|
|
{
|
|
...
|
|
});
|
|
|
|
A non-static class member function adapted to a nullary token using
|
|
`std::bind()`:
|
|
|
|
void my_class::nullary_handler()
|
|
{
|
|
...
|
|
}
|
|
...
|
|
boost::asio::post(...,
|
|
std::bind(&my_class::nullary_handler, this));
|
|
|
|
A non-static class member function adapted to a nullary token using
|
|
`boost::bind()`:
|
|
|
|
void my_class::nullary_handler()
|
|
{
|
|
...
|
|
}
|
|
...
|
|
boost::asio::post(...,
|
|
boost::bind(&my_class::nullary_handler, this));
|
|
|
|
Using [link boost_asio.reference.use_future use_future] as a nullary token:
|
|
|
|
std::future<void> f = boost::asio::post(..., boost::asio::use_future);
|
|
...
|
|
f.get();
|
|
|
|
Using [link boost_asio.reference.use_awaitable use_awaitable] as a nullary token:
|
|
|
|
boost::asio::awaitable<void> my_coroutine()
|
|
{
|
|
...
|
|
co_await boost::asio::post(..., boost::asio::use_awaitable);
|
|
...
|
|
}
|
|
|
|
[endsect]
|