* Address bind_handler ambiguous overload error when boost/bind/std_placeholders.hpp is included
Previously, the implementation of bind_handler made the assumption
that the trait boost::is_placeholder would be false for types
corresponding to values in the std::placeholders namespace.
However, boost/bind commit c85b31e3d200dda2a73cf0027a82c6d8e29066f8,
`Support use of standard placeholders with boost::bind`, added a new
header, boost/bind/std_placeholders.hpp, which adds specializations to
boost::is_placeholder for std::placeholders types.
When this header is included before a use of boost::bind_handler, it
results in compiler errors like the following, due to an internal
helper function having overloads for
enable_if<boost::is_placeholder...> and
enable_if<std::is_placeholder...>, which were previously assumed to be
mutually exclusive, but for which both conditions now are true:
../../../boost/beast/core/detail/bind_handler.hpp:126:18: error: call of overloaded 'extract(std::_Placeholder<1>, boost::beast::detail::tuple<int&&>)' is ambiguous
126 | h(extract(detail::get<S>(std::move(args)),
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
127 | std::forward<ValsTuple>(vals))...);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This header is included in boost/bind/bind.hpp, and is transitively
included by headers in many boost libraries including:
algorithm
asio
atomic
graph
msm
multi_index
property_tree
ptr_container
python
signals2
test
thread
Making it possible that an include from one of these libraries will
randomly cause bind_handler to fail to compile.
This change addresses the issue by eliminating one of the ambiguous
overloads and ensuring that boost/bind/std_placeholders.hpp is
included in the bind_handler implementation file, so that the
enable_if<boost::is_placeholder...> overload can handle both
boost::placeholders and std::placeholders values. It also explicitly
adds a boost/bind/std_placeholders.hpp include to the bind_handler
unit test to prevent this issue from regressing.
* Address boost/bind/std_placeholders.hpp feature guards
boost/bind/std_placeholders.hpp has the following feature guards:
if !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL) && !defined(BOOST_NO_CXX11_DECLTYPE) && !defined(BOOST_NO_CXX11_HDR_TYPE_TRAITS)
If this check fails, it will not detect std::placeholders values as
placeholders, making the previous solution fail.
This update restores the std::is_placeholder overload and adjusts the
SFINAE for the boost::is_placeholder overload so that it triggers only
if std::is_placeholder is false, making bind_handler work regardless
of whether std_placeholders.hpp's feature guard applies.
---------
Co-authored-by: Edward Nolan <enolan@maystreet.com>
buffers_generator uses default_completion.
websocket::stream has a rebinding constructor.
ssl_stream has a rebind_executor member.
basic_stream has rebinding constructor.
- websocket supports cancellation.
- Iterating test for ws cancellation.
- Only terminal cancellation is forwarded by default.
- basic_stream supports cancellation.
- supported cancellation is documented.
- http cancellation additions.
- Added cancellation_slot tests to http, utils and saved_handler.
- Added post to write.cpp, to avoid SIGSEV in test.
- Refresher describes cancellation in more detail.
fix#1853, close#1859, close#1866
After calling the DynamicBuffer commit() function the
buffer returned from prepare() can be invalidated but
the ostream kept using it.
fix#793, close#1791, close#1793
This brings file_win32 in sync with the documentation.
Previously, the path passed to open worked if encoded in the system
codepage (which is almost never UTF-8).
Now, the path must be encoded as UTF-8, as stated in the
documentation.
Adapt file tests so that for file_win32 all paths include a unicorn
character.
C++14 or later is required to support completion tokens that use
per-operation return type deduction. For C++11, a completion
token's async_result specialisation must still provide the nested
typedef `return_type`.
`asio::coroutine` is an extension, which is not part of
the Networking TS, so the `net` alias is not appropriate in this case.
Signed-off-by: Damian Jarek <damian.jarek93@gmail.com>
close#1570
`std::launder` must be used whenever placement-new of an unknown type
is performed and the result of the placement-new expression is discarded.
Signed-off-by: Damian Jarek <damian.jarek93@gmail.com>
Edward NolanandEdward Nolan
Klemens
Christopher Kohlhoff
Glen Fernandes
Giovanni Mascellani
Richard Hodges
Cristian Morales Vega
Mika Fischer
Vinnie Falco
Damian Jarek