<div dir="ltr">I turn to VS 2017 and everything is OK. So if you really need use boost.asio, you can try that.</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Dec 24, 2019 at 11:46 AM Leo Carreon via Boost-users &lt;<a href="mailto:boost-users@lists.boost.org">boost-users@lists.boost.org</a>&gt; wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="ltr">
<div dir="ltr">
<div style="font-size:12pt;font-family:Calibri;color:rgb(0,0,0)">
<div>Hi Boost Users,</div>
<div> </div>
<div>I am building Boost 1.72.0 in 64-bit mode with the flag /std:c++latest 
using Visual Studio 2019 16.4.2 and I am encountering the following 
issues:</div>
<div> </div>
<div>.\boost/asio/async_result.hpp(44): error C2062: type &#39;bool&#39; 
unexpected</div>
<div>.\boost/asio/async_result.hpp(45): error C2143: syntax error: missing &#39;;&#39; 
before &#39;{&#39;</div>
<div>.\boost/asio/async_result.hpp(45): error C2447: &#39;{&#39;: missing function 
header (old-style formal list?)</div>
<div>.\boost/asio/async_result.hpp(56): error C7568: argument list missing after 
assumed function template &#39;callable_with&#39;</div>
<div>.\boost/asio/async_result.hpp(58): note: see reference to class template 
instantiation 
&#39;boost::asio::detail::is_completion_handler_for&lt;T,R(Args...)&gt;&#39; being 
compiled</div>
<div>.\boost/asio/async_result.hpp(56): error C2059: syntax error: &#39;&gt;&#39;</div>
<div>.\boost/asio/async_result.hpp(57): error C3770: &#39;unknown-type&#39;: is not a 
valid base class</div>
<div>.\boost/asio/async_result.hpp(63): error C2062: type &#39;bool&#39; 
unexpected</div>
<div>.\boost/asio/async_result.hpp(64): error C2065: &#39;T&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(64): error C2923: 
&#39;boost::asio::detail::is_completion_signature&#39;: &#39;T&#39; is not a valid template type 
argument for parameter &#39;T&#39;</div>
<div>.\boost/asio/async_result.hpp(64): error C2955: 
&#39;boost::asio::detail::is_completion_signature&#39;: use of class template requires 
template argument list</div>
<div>.\boost/asio/async_result.hpp(34): note: see declaration of 
&#39;boost::asio::detail::is_completion_signature&#39;</div>
<div>.\boost/asio/async_result.hpp(69): error C2061: syntax error: identifier 
&#39;completion_signature&#39;</div>
<div>.\boost/asio/async_result.hpp(70): error C2062: type &#39;bool&#39; 
unexpected</div>
<div>.\boost/asio/async_result.hpp(71): error C2065: &#39;T&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(71): error C2065: &#39;Signature&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(71): error C2923: 
&#39;boost::asio::detail::is_completion_handler_for&#39;: &#39;T&#39; is not a valid template 
type argument for parameter &#39;T&#39;</div>
<div>.\boost/asio/async_result.hpp(71): error C2923: 
&#39;boost::asio::detail::is_completion_handler_for&#39;: &#39;Signature&#39; is not a valid 
template type argument for parameter &#39;Signature&#39;</div>
<div>.\boost/asio/async_result.hpp(71): error C2955: 
&#39;boost::asio::detail::is_completion_handler_for&#39;: use of class template requires 
template argument list</div>
<div>.\boost/asio/async_result.hpp(50): note: see declaration of 
&#39;boost::asio::detail::is_completion_handler_for&#39;</div>
<div>.\boost/asio/async_result.hpp(105): error C2039: &#39;completion_signature&#39;: is 
not a member of &#39;boost::asio&#39;</div>
<div>.\boost/asio/async_result.hpp(25): note: see declaration of 
&#39;boost::asio&#39;</div>
<div>.\boost/asio/async_result.hpp(105): error C2061: syntax error: identifier 
&#39;completion_signature&#39;</div>
<div>.\boost/asio/async_result.hpp(144): error C2061: syntax error: identifier 
&#39;completion_handler_for&#39;</div>
<div>.\boost/asio/async_result.hpp(190): note: see reference to class template 
instantiation &#39;boost::asio::async_result&lt;CompletionToken&gt;&#39; being 
compiled</div>
<div>.\boost/asio/async_result.hpp(144): error C2988: unrecognizable template 
declaration/definition</div>
<div>.\boost/asio/async_result.hpp(144): error C2059: syntax error: &#39;,&#39;</div>
<div>.\boost/asio/async_result.hpp(150): error C2334: unexpected token(s) 
preceding &#39;{&#39;; skipping apparent function body</div>
<div>.\boost/asio/async_result.hpp(194): error C2039: &#39;completion_signature&#39;: is 
not a member of &#39;boost::asio&#39;</div>
<div>.\boost/asio/async_result.hpp(25): note: see declaration of 
&#39;boost::asio&#39;</div>
<div>.\boost/asio/async_result.hpp(194): error C2061: syntax error: identifier 
&#39;completion_signature&#39;</div>
<div>.\boost/asio/async_result.hpp(195): error C2065: &#39;Signature&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(196): error C2977: 
&#39;boost::asio::async_result&#39;: too many template arguments</div>
<div>.\boost/asio/async_result.hpp(107): note: see declaration of 
&#39;boost::asio::async_result&#39;</div>
<div>.\boost/asio/async_result.hpp(198): error C2913: explicit specialization; 
&#39;boost::asio::async_result&#39; is not a specialization of a class template</div>
<div>.\boost/asio/async_result.hpp(205): error C2039: &#39;completion_signature&#39;: is 
not a member of &#39;boost::asio&#39;</div>
<div>.\boost/asio/async_result.hpp(25): note: see declaration of 
&#39;boost::asio&#39;</div>
<div>.\boost/asio/async_result.hpp(205): error C2061: syntax error: identifier 
&#39;completion_signature&#39;</div>
<div>.\boost/asio/async_result.hpp(211): error C2065: &#39;Signature&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(251): note: see reference to class template 
instantiation &#39;boost::asio::async_completion&lt;CompletionToken&gt;&#39; being 
compiled</div>
<div>.\boost/asio/async_result.hpp(250): error C2065: &#39;Signature&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(250): error C2955: 
&#39;boost::asio::async_result&#39;: use of class template requires template argument 
list</div>
<div>.\boost/asio/async_result.hpp(195): note: see declaration of 
&#39;boost::asio::async_result&#39;</div>
<div>.\boost/asio/async_result.hpp(258): error C2955: 
&#39;boost::asio::async_result&#39;: use of class template requires template argument 
list</div>
<div>.\boost/asio/async_result.hpp(195): note: see declaration of 
&#39;boost::asio::async_result&#39;</div>
<div>.\boost/asio/async_result.hpp(259): note: see reference to class template 
instantiation 
&#39;boost::asio::detail::async_result_helper&lt;CompletionToken,Signature&gt;&#39; 
being compiled</div>
<div>.\boost/asio/async_result.hpp(288): error C2672: 
&#39;boost::asio::detail::async_result_initiate_memfn_helper&#39;: no matching 
overloaded function found</div>
<div>.\boost/asio/async_result.hpp(292): note: see reference to class template 
instantiation 
&#39;boost::asio::detail::async_result_has_initiate_memfn&lt;CompletionToken,Signature&gt;&#39; 
being compiled</div>
<div>.\boost/asio/async_result.hpp(290): error C3206: 
&#39;boost::asio::detail::async_result_initiate_memfn_helper&#39;: invalid template 
argument for &#39;T&#39;, missing template argument list on class template 
&#39;boost::asio::async_result&#39;</div>
<div>.\boost/asio/async_result.hpp(281): note: see declaration of 
&#39;boost::asio::detail::async_result_initiate_memfn_helper&#39;</div>
<div>.\boost/asio/async_result.hpp(290): error C3206: 
&#39;boost::asio::detail::async_result_initiate_memfn_helper&#39;: invalid template 
argument for &#39;&lt;unnamed-symbol&gt;&#39;, missing template argument list on class 
template &#39;boost::asio::async_result&#39;</div>
<div>.\boost/asio/async_result.hpp(278): note: see declaration of 
&#39;boost::asio::detail::async_result_initiate_memfn_helper&#39;</div>
<div>.\boost/asio/async_result.hpp(350): error C2039: &#39;completion_signature&#39;: is 
not a member of &#39;boost::asio&#39;</div>
<div>.\boost/asio/async_result.hpp(25): note: see declaration of 
&#39;boost::asio&#39;</div>
<div>.\boost/asio/async_result.hpp(350): error C2061: syntax error: identifier 
&#39;completion_signature&#39;</div>
<div>.\boost/asio/async_result.hpp(353): error C2065: &#39;Signature&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(353): error C2923: 
&#39;boost::asio::detail::async_result_has_initiate_memfn&#39;: &#39;Signature&#39; is not a 
valid template type argument for parameter &#39;Signature&#39;</div>
<div>.\boost/asio/async_result.hpp(354): error C2760: syntax error: unexpected 
token &#39;&gt;&#39;, expected &#39;expression&#39;</div>
<div>.\boost/asio/async_result.hpp(359): error C2065: &#39;Initiation&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(359): error C2065: &#39;initiation&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(360): error C2065: &#39;token&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(361): error C2065: &#39;Args&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(361): warning C4346: 
&#39;boost::asio::detail::async_result_has_initiate_memfn::value&#39;: dependent name is 
not a type</div>
<div>.\boost/asio/async_result.hpp(361): note: prefix with &#39;typename&#39; to 
indicate a type</div>
<div>.\boost/asio/async_result.hpp(361): error C2988: unrecognizable template 
declaration/definition</div>
<div>.\boost/asio/async_result.hpp(361): error C2059: syntax error: &#39;...&#39;</div>
<div>.\boost/asio/async_result.hpp(362): error C2143: syntax error: missing &#39;;&#39; 
before &#39;{&#39;</div>
<div>.\boost/asio/async_result.hpp(362): error C2447: &#39;{&#39;: missing function 
header (old-style formal list?)</div>
<div>.\boost/asio/async_result.hpp(370): error C2039: &#39;completion_signature&#39;: is 
not a member of &#39;boost::asio&#39;</div>
<div>.\boost/asio/async_result.hpp(25): note: see declaration of 
&#39;boost::asio&#39;</div>
<div>.\boost/asio/async_result.hpp(370): error C2061: syntax error: identifier 
&#39;completion_signature&#39;</div>
<div>.\boost/asio/async_result.hpp(373): error C2065: &#39;Signature&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(373): error C2923: 
&#39;boost::asio::detail::async_result_has_initiate_memfn&#39;: &#39;Signature&#39; is not a 
valid template type argument for parameter &#39;Signature&#39;</div>
<div>.\boost/asio/async_result.hpp(374): error C2065: &#39;Signature&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(375): error C2065: &#39;Initiation&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(375): error C2065: &#39;initiation&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(376): error C2065: &#39;token&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(377): error C2065: &#39;Args&#39;: undeclared 
identifier</div>
<div>.\boost/asio/async_result.hpp(377): warning C4346: 
&#39;boost::asio::detail::async_result_has_initiate_memfn::value&#39;: dependent name is 
not a type</div>
<div>.\boost/asio/async_result.hpp(377): note: prefix with &#39;typename&#39; to 
indicate a type</div>
<div>.\boost/asio/async_result.hpp(377): error C2988: unrecognizable template 
declaration/definition</div>
<div>.\boost/asio/async_result.hpp(377): error C2059: syntax error: &#39;...&#39;</div>
<div>.\boost/asio/async_result.hpp(378): error C2143: syntax error: missing &#39;;&#39; 
before &#39;{&#39;</div>
<div>.\boost/asio/async_result.hpp(378): error C2447: &#39;{&#39;: missing function 
header (old-style formal list?)</div>
<div>.\boost/asio/async_result.hpp(483): error C7568: argument list missing 
after assumed function template &#39;completion_handler_for&#39;</div>
<div>.\boost/asio/async_result.hpp(487): note: see reference to class template 
instantiation &#39;boost::asio::detail::initiation_archetype&lt;Signature&gt;&#39; being 
compiled</div>
<div>.\boost/asio/async_result.hpp(484): error C2061: syntax error: identifier 
&#39;CompletionHandler&#39;</div>
<div>.\boost/asio/async_result.hpp(491): error C2061: syntax error: identifier 
&#39;completion_signature&#39;</div>
<div>.\boost/asio/async_result.hpp(492): error C2062: type &#39;bool&#39; 
unexpected</div>
<div>.\boost/asio/async_result.hpp(493): error C2143: syntax error: missing &#39;;&#39; 
before &#39;{&#39;</div>
<div>.\boost/asio/async_result.hpp(493): error C2447: &#39;{&#39;: missing function 
header (old-style formal list?)</div>
<div>.\boost/asio/post.hpp(56): error C2039: &#39;completion_token_for&#39;: is not a 
member of &#39;boost::asio&#39;</div>
<div>.\boost/asio/post.hpp(27): note: see declaration of &#39;boost::asio&#39;</div>
<div>.\boost/asio/post.hpp(56): error C2061: syntax error: identifier 
&#39;completion_token_for&#39;</div>
<div>.\boost/asio/post.hpp(56): error C2988: unrecognizable template 
declaration/definition</div>
<div>.\boost/asio/post.hpp(56): error C2059: syntax error: &#39;&gt;&#39;</div>
<div>.\boost/asio/post.hpp(94): error C2039: &#39;completion_token_for&#39;: is not a 
member of &#39;boost::asio&#39;</div>
<div>.\boost/asio/post.hpp(27): note: see declaration of &#39;boost::asio&#39;</div>
<div>.\boost/asio/post.hpp(94): error C2061: syntax error: identifier 
&#39;completion_token_for&#39;</div>
<div>.\boost/asio/post.hpp(95): error C2988: unrecognizable template 
declaration/definition</div>
<div>.\boost/asio/post.hpp(95): error C2059: syntax error: &#39;&gt;&#39;</div>
<div>.\boost/asio/post.hpp(107): error C2039: &#39;completion_token_for&#39;: is not a 
member of &#39;boost::asio&#39;</div>
<div>.\boost/asio/post.hpp(27): note: see declaration of &#39;boost::asio&#39;</div>
<div>.\boost/asio/post.hpp(107): error C2061: syntax error: identifier 
&#39;completion_token_for&#39;</div>
<div>.\boost/asio/post.hpp(108): error C2988: unrecognizable template 
declaration/definition</div>
<div>.\boost/asio/post.hpp(108): error C2059: syntax error: &#39;&gt;&#39;</div>
<div>.\boost/asio/impl/post.hpp(81): error C2039: &#39;completion_token_for&#39;: is not 
a member of &#39;boost::asio&#39;</div>
<div>.\boost/asio/impl/post.hpp(26): note: see declaration of 
&#39;boost::asio&#39;</div>
<div>.\boost/asio/impl/post.hpp(81): error C2061: syntax error: identifier 
&#39;completion_token_for&#39;</div>
<div>.\boost/asio/impl/post.hpp(81): error C2988: unrecognizable template 
declaration/definition</div>
<div>.\boost/asio/impl/post.hpp(81): error C2059: syntax error: &#39;&gt;&#39;</div>
<div>.\boost/asio/impl/post.hpp(84): error C2143: syntax error: missing &#39;;&#39; 
before &#39;{&#39;</div>
<div>.\boost/asio/impl/post.hpp(84): error C2447: &#39;{&#39;: missing function header 
(old-style formal list?)</div>
<div>.\boost/asio/impl/post.hpp(90): error C2039: &#39;completion_token_for&#39;: is not 
a member of &#39;boost::asio&#39;</div>
<div>.\boost/asio/impl/post.hpp(26): note: see declaration of 
&#39;boost::asio&#39;</div>
<div>.\boost/asio/impl/post.hpp(90): error C2061: syntax error: identifier 
&#39;completion_token_for&#39;</div>
<div>.\boost/asio/impl/post.hpp(90): error C2988: unrecognizable template 
declaration/definition</div>
<div>.\boost/asio/impl/post.hpp(90): error C2059: syntax error: &#39;&gt;&#39;</div>
<div>.\boost/asio/impl/post.hpp(94): error C2143: syntax error: missing &#39;;&#39; 
before &#39;{&#39;</div>
<div>.\boost/asio/impl/post.hpp(94): error C2447: &#39;{&#39;: missing function header 
(old-style formal list?)</div>
<div>.\boost/asio/impl/post.hpp(100): error C2039: &#39;completion_token_for&#39;: is 
not a member of &#39;boost::asio&#39;</div>
<div>.\boost/asio/impl/post.hpp(26): note: see declaration of 
&#39;boost::asio&#39;</div>
<div>.\boost/asio/impl/post.hpp(100): error C2061: syntax error: identifier 
&#39;completion_token_for&#39;</div>
<div>.\boost/asio/impl/post.hpp(100): error C2988: unrecognizable template 
declaration/definition</div>
<div>.\boost/asio/impl/post.hpp(100): error C2059: syntax error: &#39;&gt;&#39;</div>
<div>.\boost/asio/impl/post.hpp(105): error C2143: syntax error: missing &#39;;&#39; 
before &#39;{&#39;</div>
<div>.\boost/asio/impl/post.hpp(105): error C2447: &#39;{&#39;: missing function header 
(old-style formal list?)</div>
<div>.\boost/asio/detail/buffer_sequence_adapter.hpp(106): error C2955: 
&#39;boost::asio::detail::buffer_sequence_adapter_base&#39;: use of class template 
requires template argument list</div>
<div>.\boost/asio/detail/buffer_sequence_adapter.hpp(30): note: see declaration 
of &#39;boost::asio::detail::buffer_sequence_adapter_base&#39;</div>
<div>.\boost/asio/detail/buffer_sequence_adapter.hpp(208): note: see reference 
to class template instantiation 
&#39;boost::asio::detail::buffer_sequence_adapter&lt;Buffer,Buffers&gt;&#39; being 
compiled</div>
<div>.\boost/asio/detail/buffer_sequence_adapter.hpp(116): error C2143: syntax 
error: missing &#39;;&#39; before &#39;*&#39;</div>
<div>.\boost/asio/detail/buffer_sequence_adapter.hpp(116): fatal error C1003: 
error count exceeds 100; stopping compilation</div>
<div> </div>
<div>Has anyone else encountered the same issues and how to resolve them?</div>
<div> </div>
<div>It appears that the macro BOOST_ASIO_CONCEPT is the one causing the 
issue.  This macro seems to have the value “concept bool” which causes the 
complaint from the compiler.</div>
<div> </div>
<div>Kind regards,</div>
<div>Leo</div>
<div> </div></div></div></div>
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</blockquote></div>