Alternative를 사용해 GCC/G++ 등록

• Terminal 실행

• Check GCC Version
  대부분 GCC는 아마 "/usr/local" 또는 "/opt/" 아래에 위치해 있을 것입니다.
  gcc의 위치를 확인 후 gcc/g++를 등록합니다.
  마지막 숫자는 우선순위(priority)입니다. 어떤 숫자든 상관 없습니다.

  # sudo ./configure_gcc_alternatives.sh
  sudo update-alternatives --install /usr/bin/gcc gcc /usr/local/gcc-10.1.0/bin/gcc-10.1 10
  sudo update-alternatives --install /usr/bin/gcc gcc /opt/gcc-9.1.0/bin/gcc-9.1 20
  
  sudo update-alternatives --install /usr/bin/g++ g++ /usr/local/gcc-10.1.0/bin/g++-10.1 10
  sudo update-alternatives --install /usr/bin/g++ g++ /opt/gcc-9.1.0/bin/g++-9.1 20
  
  sudo update-alternatives --install /usr/bin/cc cc /usr/bin/gcc 30
  sudo update-alternatives --set cc /usr/bin/gcc
  
  sudo update-alternatives --install /usr/bin/c++ c++ /usr/bin/g++ 30
  sudo update-alternatives --set c++ /usr/bin/g++

• 만약 업데이트가 완료되면 아래와 같이 출력됩니다.

  $ sudo ./configure_gcc_alternatives.sh
  update-alternatives: using /usr/local/gcc-10.1.0/bin/gcc-10.1 to provide /usr/bin/gcc (gcc) in auto mode
  update-alternatives: using /opt/gcc-9.1.0/bin/gcc-9.1 to provide /usr/bin/gcc (gcc) in auto mode
  update-alternatives: using /usr/local/gcc-10.1.0/bin/g++-10.1 to provide /usr/bin/g++ (g++) in auto mode
  update-alternatives: using /opt/gcc-9.1.0/bin/g++-9.1 to provide /usr/bin/g++ (g++) in auto mode

alternative를 사용하여 GCC/G++ 선택

GCC 선택

• Command

  sudo update-alternatives --config gcc

• Example

  $ sudo update-alternatives --config gcc
  There are 2 choices for the alternative gcc (providing /usr/bin/gcc).
  
    Selection    Path                                Priority   Status
  ------------------------------------------------------------
  * 0            /opt/gcc-9.1.0/bin/gcc-9.1           20        auto mode
    1            /opt/gcc-9.1.0/bin/gcc-9.1           20        manual mode
    2            /usr/local/gcc-10.1.0/bin/gcc-10.1   10        manual mode
  
  Press <enter> to keep the current choice[*], or type selection number: 2
  update-alternatives: using /usr/local/gcc-10.1.0/bin/gcc-10.1 to provide /usr/bin/gcc (gcc) in manual mode

G++ 선택

• Command

  sudo update-alternatives --config g++

• Example

  There are 2 choices for the alternative g++ (providing /usr/bin/g++).
  
    Selection    Path                                Priority   Status
  ------------------------------------------------------------
  * 0            /opt/gcc-9.1.0/bin/g++-9.1           20        auto mode
    1            /opt/gcc-9.1.0/bin/g++-9.1           20        manual mode
    2            /usr/local/gcc-10.1.0/bin/g++-10.1   10        manual mode
  
  Press <enter> to keep the current choice[*], or type selection number: 2
  update-alternatives: using /usr/local/gcc-10.1.0/bin/g++-10.1 to provide /usr/bin/g++ (g++) in manual mode

GCC/G++ Version 확인

아래 명령을 통해 버전을 확인합니다.

• Command

  gcc --version
  g++ --version

• Example

  $ gcc --version
  gcc (GCC) 10.1.0
  Copyright (C) 2020 Free Software Foundation, Inc.
  This is free software; see the source for copying conditions.  There is NO
  warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  
  $ g++ --version
  g++ (GCC) 10.1.0
  Copyright (C) 2020 Free Software Foundation, Inc.
  This is free software; see the source for copying conditions.  There is NO
  warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.