gcc多版本切换

执行以下命令

sudo apt install build-essential
$ sudo apt -y install gcc-7 g++-7 gcc-8 g++-8 gcc-9 g++-9

sudo update-alternatives –install /usr/bin/gcc gcc /usr/bin/gcc-7 7

sudo update-alternatives –install /usr/bin/g++ g++ /usr/bin/g++-7 7

sudo update-alternatives –install /usr/bin/gcc gcc /usr/bin/gcc-8 8

sudo update-alternatives –install /usr/bin/g++ g++ /usr/bin/g++-8 8

sudo update-alternatives –install /usr/bin/gcc gcc /usr/bin/gcc-9 9

sudo update-alternatives –install /usr/bin/g++ g++ /usr/bin/g++-9 9

$ sudo update-alternatives –config gcc
There are 3 choices for the alternative gcc (providing /usr/bin/gcc).
Selection Path Priority Status————————————————————
0 /usr/bin/gcc-9 9 auto mode
1 /usr/bin/gcc-7 7 manual mode*
2 /usr/bin/gcc-8 8 manual mode
3 /usr/bin/gcc-9 9 manual mode
Press to keep the current choice[*], or type selection number:

$ sudo update-alternatives –config g++
There are 3 choices for the alternative g++ (providing /usr/bin/g++).
Selection Path Priority Status————————————————————*
0 /usr/bin/g++-9 9 auto mode
1 /usr/bin/g++-7 7 manual mode
2 /usr/bin/g++-8 8 manual mode
3 /usr/bin/g++-9 9 manual mode
Press to keep the current choice[*], or type selection number:

$ gcc –version
$ g++ –version