boost is THE C++ library out there. Many features were introduced in boost before adopted in C++ standard. I want to have it installed on my local Mac laptop, so I can easily play with it.
homebrew formula not working
brew install boost is the first thing I did and it looked like it "worked". But it didn't install things like libboost_fiber. It's simply missing from /usr/local/Cellar/boost/<boost_version>/lib. It's not obvious why that's the case by reading the formula. I don't know Ruby as well. homebrew does't seem to be the best option here, especially, I want to have more control over the installation.
System default c++ compiler
The default compiler that comes with XCode is clang. You can find gcc, g++, clang, clang++ driver binaries in /usr/bin. They all do pretty much the same thing. There's no difference between g++ and clang++ for example.
/u/bin ❯❯❯ g++ -x c++ -v -E /dev/null
Apple LLVM version 10.0.0 (clang-1000.11.45.5)
Target: x86_64-apple-darwin17.7.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
"/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang" -cc1 -triple x86_64-apple-macosx10.13.0 -Wdeprecated-objc-isa-usage -Werror=deprecated-objc-isa-usage -E -disable-free -disable-llvm-verifier -discard-value-names -main-file-name null -mrelocation-model pic -pic-level 2 -mthread-model posix -mdisable-fp-elim -fno-strict-return -masm-verbose -munwind-tables -target-cpu penryn -dwarf-column-info -debugger-tuning=lldb -target-linker-version 409.12 -v -resource-dir /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/10.0.0 -stdlib=libc++ -fdeprecated-macro -fdebug-compilation-dir /usr/bin -ferror-limit 19 -fmessage-length 123 -stack-protector 1 -fblocks -fencode-extended-block-signature -fobjc-runtime=macosx-10.13.0 -fcxx-exceptions -fexceptions -fmax-type-align=16 -fdiagnostics-show-option -fcolor-diagnostics -o - -x c++ /dev/null
clang -cc1 version 10.0.0 (clang-1000.11.45.5) default target x86_64-apple-darwin17.7.0
ignoring nonexistent directory "/usr/include/c++/v1"
#include "..." search starts here:
#include <...> search starts here:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1
/usr/local/include
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/10.0.0/include
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include
/usr/include
/System/Library/Frameworks (framework directory)
/Library/Frameworks (framework directory)
End of search list.
# 1 "/dev/null"
# 1 "<built-in>" 1
# 1 "<built-in>" 3
# 373 "<built-in>" 3
# 1 "<command line>" 1
# 1 "<built-in>" 2
# 1 "/dev/null" 2
vs.
/u/bin ❯❯❯ clang++ -x c++ -v -E /dev/null
Apple LLVM version 10.0.0 (clang-1000.11.45.5)
Target: x86_64-apple-darwin17.7.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
"/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang" -cc1 -triple x86_64-apple-macosx10.13.0 -Wdeprecated-objc-isa-usage -Werror=deprecated-objc-isa-usage -E -disable-free -disable-llvm-verifier -discard-value-names -main-file-name null -mrelocation-model pic -pic-level 2 -mthread-model posix -mdisable-fp-elim -fno-strict-return -masm-verbose -munwind-tables -target-cpu penryn -dwarf-column-info -debugger-tuning=lldb -target-linker-version 409.12 -v -resource-dir /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/10.0.0 -stdlib=libc++ -fdeprecated-macro -fdebug-compilation-dir /usr/bin -ferror-limit 19 -fmessage-length 123 -stack-protector 1 -fblocks -fencode-extended-block-signature -fobjc-runtime=macosx-10.13.0 -fcxx-exceptions -fexceptions -fmax-type-align=16 -fdiagnostics-show-option -fcolor-diagnostics -o - -x c++ /dev/null
clang -cc1 version 10.0.0 (clang-1000.11.45.5) default target x86_64-apple-darwin17.7.0
ignoring nonexistent directory "/usr/include/c++/v1"
#include "..." search starts here:
#include <...> search starts here:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1
/usr/local/include
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/10.0.0/include
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include
/usr/include
/System/Library/Frameworks (framework directory)
/Library/Frameworks (framework directory)
End of search list.
# 1 "/dev/null"
# 1 "<built-in>" 1
# 1 "<built-in>" 3
# 373 "<built-in>" 3
# 1 "<command line>" 1
# 1 "<built-in>" 2
# 1 "/dev/null" 2
Well, which C++ standards does it support?
/u/bin ❯❯❯ clang++ -x c++ -std=c++20 -v -E /dev/null
...
error: invalid value 'c++20' in '-std=c++20'
note: use 'c++98' or 'c++03' for 'ISO C++ 1998 with amendments' standard
note: use 'gnu++98' or 'gnu++03' for 'ISO C++ 1998 with amendments and GNU extensions' standard
note: use 'c++11' for 'ISO C++ 2011 with amendments' standard
note: use 'gnu++11' for 'ISO C++ 2011 with amendments and GNU extensions' standard
note: use 'c++14' for 'ISO C++ 2014 with amendments' standard
note: use 'gnu++14' for 'ISO C++ 2014 with amendments and GNU extensions' standard
note: use 'c++17' for 'ISO C++ 2017 with amendments' standard
note: use 'gnu++17' for 'ISO C++ 2017 with amendments and GNU extensions' standard
note: use 'c++2a' for 'Working draft for ISO C++ 2020' standard
note: use 'gnu++2a' for 'Working draft for ISO C++ 2020 with GNU extensions' standard
Nice, it supports up to C++20!
Install Boost
Follow the instructions from Boost website, https://www.boost.org/doc/libs/1_69_0/more/getting_started/unix-variants.html#easy-build-and-install. Since boost is a head-only library, which means you get most of the features without having to "install" anything. But I want fiber, which depends on Boost.context; so I have to build it.
However when you simply do b2 install it will print you something like
Performing configuration checks
- default address-model : 64-bit
- default architecture : x86
- C++11 mutex : no
- lockfree boost::atomic_flag : yes
- Boost.Config Feature Check: cxx11_auto_declarations : no
- Boost.Config Feature Check: cxx11_constexpr : no
- Boost.Config Feature Check: cxx11_defaulted_functions : no
- Boost.Config Feature Check: cxx11_final : no
- Boost.Config Feature Check: cxx11_hdr_mutex : no
- Boost.Config Feature Check: cxx11_hdr_tuple : no
- Boost.Config Feature Check: cxx11_lambdas : no
- Boost.Config Feature Check: cxx11_noexcept : no
- Boost.Config Feature Check: cxx11_nullptr : no
- Boost.Config Feature Check: cxx11_rvalue_references : no
Wait, I thought we support all the way to c++20? Well not by default. We have to set cxxflags so the compiler would know to use the latest standard.
./b2 cxxflags="-std=c++14" install looks much better
Performing configuration checks
- default address-model : 64-bit
- default architecture : x86
- C++11 mutex : yes
- lockfree boost::atomic_flag : yes
- Boost.Config Feature Check: cxx11_auto_declarations : yes
- Boost.Config Feature Check: cxx11_constexpr : yes
- Boost.Config Feature Check: cxx11_defaulted_functions : yes
- Boost.Config Feature Check: cxx11_final : yes
- Boost.Config Feature Check: cxx11_hdr_mutex : yes
- Boost.Config Feature Check: cxx11_hdr_tuple : yes
- Boost.Config Feature Check: cxx11_lambdas : yes
- Boost.Config Feature Check: cxx11_noexcept : yes
- Boost.Config Feature Check: cxx11_nullptr : yes
- Boost.Config Feature Check: cxx11_rvalue_references : yes
- Boost.Config Feature Check: cxx11_template_aliases : yes
- Boost.Config Feature Check: cxx11_thread_local : yes
- Boost.Config Feature Check: cxx11_variadic_templates : yes
Build
Download simple.cpp from boost/fiber/examples. And build it with
$ clang++ -std=c++14 -I /usr/local/opt/boost/include simple.cpp -L /usr/local/opt/boost/lib -lboost_fiber -lboost_context
$
Hooray!