How to compile #include for clang o

问题:

I am trying to get the #include <experimental/any> to compile in my C++ program on clang OSX

// test.cpp
#include <experimental/any>

int main() {
  return 0;
}

Tried following commands/options as learnt from here

clang++ -std=c++14 test.cpp -o test -std=c++1z -stdlib=libc++
clang++ -std=c++1x test.cpp -o test -std=c++1z -stdlib=libc++
clang++ -std=c++1y test.cpp -o test -std=c++1z -stdlib=libc++
clang++ -std=c++1z test.cpp -o test -std=c++1z -stdlib=libc++

But it doesn't compile & complains of the following error:

fatal error: 'experimental/any' file not found

clang++ --version yields following:

Apple LLVM version 8.1.0 (clang-802.0.42)
Target: x86_64-apple-darwin16.5.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

How can I get #include <experimental/any> to compile?

Should I upgrade clang on my machine?

Is C++17 supported on clang currently as of today? If yes how can get the support for it?

回答1:

For OSX 10.12.5 (using Xcode Developer tools), we get

> clang++ -v
Apple LLVM version 8.1.0 (clang-802.0.42)
Target: x86_64-apple-darwin16.6.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

and there is no any in /Library/Developer/CommandLineTools/usr/include/c++/v1/experimental, but only

chrono
optional    
string_view 
tuple
utility
algorithm
dynarray    
ratio   
system_error    
type_traits

So, it appears that Apple's libc++ does not provide any (there is no any in /Library/Developer/CommandLineTools/usr/include/c++/v1/ either). You must either use GCC or your own clang or boost/any.hpp, all of which you can install via homebrew.

回答2:

You misspelt it. It's "experimental", not "experimentals".

However, since Clang 4.0, you should just be using <any>.