* Added overload so member functions can provide an explicit executor.
* Added co_spawn for coro tasks.
* Added reference and overview documentation.
* Adopted awaitable cancellation model.
* Refactored implementation.
The BOOST_ASIO_HANDLER_LOCATION((file_name, line, function_name)) macro
may be used to inform the handler tracking mechanism of a source
location. This macro declares an object that is placed on the stack.
When an asynchronous operation is launched with location information, it
outputs lines using the <action> 'n^m', prior to the 'n*m' line that
signifies the beginning of the asynchronous operation. For example:
@asio|1589423304.861944|>7|ec=system:0,bytes_transferred=5
@asio|1589423304.861952|7^8|in 'async_write' (./../../../include/asio/impl/write.hpp:330)
@asio|1589423304.861952|7^8|called from 'do_write' (handler_tracking/async_tcp_echo_server.cpp:62)
@asio|1589423304.861952|7^8|called from 'operator()' (handler_tracking/async_tcp_echo_server.cpp:51)
@asio|1589423304.861952|7*8|socket@0x7ff61c008230.async_send
@asio|1589423304.861975|.8|non_blocking_send,ec=system:0,bytes_transferred=5
@asio|1589423304.861980|<7|
If std::source_location or std::experimental::source_location are
available, the use_awaitable_t token (when default-constructed or used
as a default completion token) will also cause handler tracking to
output a source location for each newly created asynchronous operation.
A use_awaitable_t object may also be explicitly constructed with location
information.
The ssl::host_name_verification class is a drop-in replacement for
ssl::rfc2818_verification, which it supersedes. The
ssl::rfc2818_verification class has been marked as deprecated.
Thanks to Arvid Norberg for providing the implementation.
The awaitable<>, co_spawn(), this_coro, detached, and redirect_error
facilities have been moved from the asio::experimental namespace to
namespace asio. As part of this change, the this_coro::token() awaitable
has been superseded by the asio::use_awaitable completion token.
Please note that the use_awaitable and redirect_error completion tokens
work only with asynchronous operations that use the new form of
async_result with member function initiate(). Furthermore, when using
use_awaitable, please be aware that the asynchronous operation is not
initiated until co_await is applied to the awaitable<>.
The epoll_reactor now supports the use of regular file descriptors with
posix::stream_descriptor, provided the I/O operations on them never fail
with EAGAIN or EWOULDBLOCK. If the descriptor cannot be added to the
epoll set using epoll_ctl, and errno is EPERM (indicating an unsupported
descriptor type), then no error condition is raised. Instead, any
operation which would require a trip through the reactor will fail.
