Mac自带Clang是一个C语言、C++、Objective-C语言的轻量级编译器。Clang是由苹果公司自己从头开发的，与GCC系统相比更加小巧，但是与GCC可以兼容。

最近编译一个c++程序时，Clang总是报错：

clang: error unsupported option '-fopenmp'

#1. 解决办法-安装GCC

##2. Homebrew(mac系统没有自带)

• Homebrew官网：https://brew.sh/

• Homebrew是一个适用于macOS、Linux的软件包管理工具。

###2.1 安装Homebrew

$ /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

###2.2 Homebrew使用

$ brew -h
Example usage:
  brew search [TEXT|/REGEX/]
  brew info [FORMULA...]
  brew install FORMULA...
  brew update
  brew upgrade [FORMULA...]
  brew uninstall FORMULA...
  brew list [FORMULA...]

Troubleshooting:
  brew config
  brew doctor
  brew install --verbose --debug FORMULA

Contributing:
  brew create [URL [--no-fetch]]
  brew edit [FORMULA...]

Further help:
  brew commands
  brew help [COMMAND]
  man brew
  https://docs.brew.sh

##3. 安装GCC

$ brew install gcc

Homebrew安装的软件一般在/usr/local/Cellar,并且会在/usr/local/bin/下创建链接。

• 查看安装的GCC

$ ls /usr/local/bin/gcc*

/usr/local/bin/gcc-10       /usr/local/bin/gcc-nm-10
/usr/local/bin/gcc-ar-10    /usr/local/bin/gcc-ranlib-10

• 查看自带的Clang

$ which clang
/Users/liuxiaojian/anaconda3/bin/clang

• mac的GCC默认链接到Clang

$ which gcc
/usr/bin/gcc

#编译程序

$ /usr/local/bin/g++-10 x.cpp -o x