c++macosboostclangmacports

Mac OS boost installed using macports collision with C++ version

Anyone know why sudo cmake --build ./build-clang --config Release results in

In file included from /opt/local/include/boost/asio/buffer.hpp:29:
/opt/local/include/boost/asio/detail/type_traits.hpp:89:12: error: no member named 'result_of' in namespace 'std'
using std::result_of;
      ~~~~~^

Despite the env variables being set?

$CC=clang
$CXX=clang++

$CC --version

Homebrew clang version 15.0.6
Target: x86_64-apple-darwin20.6.0
Thread model: posix
InstalledDir: /usr/local/opt/llvm/bin

trying to build for Mac for the first time. boost was installed using macports sudo port install boost +universal

I've heard result_of was deprecated in C++17 and removed in C++20 – how can I get around this issue? I'm working with C++20

when I add

target_compile_definitions(${TARGET_NAME}
        PRIVATE
        BOOST_ASIO_HAS_STD_INVOKE_RESULT=1)

I get the same errors

I uninstalled and reinstalled the latest version using brew and now I get /opt/local/include/cpprest/http_client.h:68:10: fatal error: 'boost/asio/ssl.hpp' file not found #include "boost/asio/ssl.hpp"

Solution

  • The problem is that at the moment, MacPorts only supports up to Boost 1.76. By default, it will use std::result_of, which has been removed in C++20.

    To solve this, you can manually define BOOST_ASIO_HAS_STD_INVOKE_RESULT, which should route usages of result_of to the C++20 compliant invoke_result within the source.

    Note, this does not guarantee all other codes are C++20 compliant.

    Alternatively, you can also manually install Boost, or install it through other package managers like Homebrew, which supports up to Boost 1.81