Boost是一个功能强大、构造精巧、跨平台、开源并且完全免费的C++程序库，有着“C++‘准’标准库”的美誉，值得每位C++程序员学习使用。

1 安装Boost

1.1 使用源码安装

下载Boost源码
解压放在任意目录，例如/usr/local/boost_1_63_0
./bootstrap.sh
./b2 headers
./b2
留意运行日志头文件目录 /usr/local/boost_1_63_0, lib目录/usr/local/boost_1_63_0/stage/lib
打开源码中index.html查看使用文档

1.2 使用Homebrew安装

下载安装HomeBrew
brew install boost
留意运行日志会显示头文件目录 /usr/local/Cellar/boost/1.60.0_2/include, lib目录/usr/local/Cellar/boost/1.60.0_2/lib

1.3 使用MacPort安装

下载安装MacPort
sudo port install boost

2 在XCode项目中使用Boost

新建一个Command Line Tool项目
在Build Setings - Header Search Paths 增加头文件目录
替换main.cpp中代码，运行！输入任意数字回车可看到结果。

#include  #include  int main(int argc, const char * argv[]) {     printf("Please input any number:");     using namespace boost::lambda;     typedef std::istream_iterator in;     std::for_each(in(std::cin), in(), std::cout << (_1 * 3) << " " );     return 0; } 

3 在XCode项目中使用Boost Lib库

Boost的很多功能都是直接在hpp头文件里实现的，比如上面的lambda例子不用导入任何lib就可以运行了。但也有一部分需要依赖指定lib库才能使用。比如下面这个正则表达式的例子:

#include  #include    int main(int argc, const char * argv[]) {     std::string   str = "2013-08-15";     boost::regex  rex("(?[0-9]{4}).*(?[0-9]{2}).*(?[0-9]{2})");     boost::smatch res;          std::string::const_iterator begin = str.begin();     std::string::const_iterator end   = str.end();          if (boost::regex_search(begin, end, res, rex))     {         std::cout << "Day:   " << res ["day"] << std::endl         << "Month: " << res ["month"] << std::endl         << "Year:  " << res ["year"] << std::endl;     } }  

3.1 使用静态库

Build Setings - Other linker flags /usr/local/boost_1_63_0/stage/lib/libboost_regex.a

使用命令行编译相当于

c++ -I /usr/local/boost_1_63_0 main.cpp -o main /usr/local/boost_1_63_0/stage/lib/libboost_regex.a ./main 

如果这里直接使用lboost_regex, Xcode默认加载动态库。实际运用中可以考虑将目录中的动态库删除，只保留静态库，并在Build Setings - Library Search Paths 增加lib文件目录。

3.2 使用动态库

1. 在Build Setings - Library Search Paths 增加lib文件目录
2. 将lib文件目录中的libboost_regex.dylib文件拖入项目
3. 确保在Build Phases - Link Bindary With Libraries中已经有该库
4. 在Build Phases - Copy Files, 复制libboost_regex.dylib到Products Directory
   使用命令行编译相当于

c++ -I /usr/local/boost_1_63_0 main.cpp -o main -L/usr/local/boost_1_63_0/stage/lib/ -lboost_regex cp /usr/local/boost_1_63_0/stage/lib/libboost_regex.dylib ./ ./main 

最终安装目录:

/usr/local/Cellar/boost/1.67.0_1 

设置头文件为/usr/local/Cellar/boost/1.67.0_1/include/,库文件为/usr/local/Cellar/boost/1.67.0_1/lib/
使用brew安装结果:

brew install boost Updating Homebrew... ==> Downloading https://homebrew.bintray.com/bottles-portable-ruby/portable-ruby-2.3.7.leopard_64.bottle.tar.gz ######################################################################## 100.0% ==> Pouring portable-ruby-2.3.7.leopard_64.bottle.tar.gz ==> Homebrew is run entirely by unpaid volunteers. Please consider donating:   https://github.com/Homebrew/brew#donations ==> Migrating tap caskroom/cask to homebrew/cask... Changing remote from https://github.com/Caskroom/homebrew-cask to https://github.com/Homebrew/homebrew-cask... Moving /usr/local/Homebrew/Library/Taps/caskroom/homebrew-cask to /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask... ==> Auto-updated Homebrew! Updated 4 taps (homebrew/science, homebrew/core, homebrew/services, homebrew/cask). ==> New Formulae amtk                                   gptfdisk                               patchelf gmt@4                                  nuxeo                                  zstd gnatsd                                 nvc ==> Renamed Formulae cdiff -> ydiff                         php56 -> php@5.6                       rebar@3 -> rebar3 crystal-lang -> crystal                php70 -> php@7.0                       saltstack -> salt geth -> ethereum                       php71 -> php@7.1                       wpcli-completion -> wp-cli-completion latexila -> gnome-latex                php72 -> php ==> Deleted Formulae arm                          ghc@8.0                      llvm@3.8                     python3 artifactory-cli-go           gnupg@2.0                    luciddb                      root@5 aws-cloudsearch              go@1.6                       mal4s                        ruby@1.9 bokken                       go@1.7                       mimetic                      ruby@2.1 boot2docker                  gpg-agent                    monotone                     tomcat@8.0 boot2docker-completion       i3                           nazghul                      ufoai dirmngr                      i3status                     node@4                       voltdb ecj                          llvm@3.7                     picolisp                     wry  ==> Downloading https://homebrew.bintray.com/bottles/boost-1.67.0_1.high_sierra.bottle.tar.gz ######################################################################## 100.0% ==> Pouring boost-1.67.0_1.high_sierra.bottle.tar.gz Error: The `brew link` step did not complete successfully The formula built, but is not symlinked into /usr/local Could not symlink include/boost/accumulators/accumulators.hpp Target /usr/local/include/boost/accumulators/accumulators.hpp is a symlink belonging to boost. You can unlink it:   brew unlink boost  To force the link and overwrite all conflicting files:   brew link --overwrite boost  To list all files that would be deleted:   brew link --overwrite --dry-run boost  Possible conflicting files are: /usr/local/include/boost/accumulators/accumulators.hpp -> /usr/local/Cellar/boost/1.60.0_2/include/boost/accumulators/accumulators.hpp /usr/local/include/boost/accumulators/accumulators_fwd.hpp -> /usr/local/Cellar/boost/1.60.0_2/include/boost/accumulators/accumulators_fwd.hpp /usr/local/include/boost/accumulators/framework/accumulator_base.hpp -> /usr/local/Cellar/boost/1.60.0_2/include/boost/accumulators/framework/accumulator_base.hpp ... ==> Summary 🍺  /usr/local/Cellar/boost/1.67.0_1: 13,506 files, 450.9MB