配置gcc

對于一個全新的Ubuntu系統(tǒng)，可能還沒有配置C語言編譯環(huán)境，這時候需要用戶自己安裝。

:~$ gcc -v
Command 'gcc' not found, but can be installed with:
sudo apt install gcc

查看版本gcc -v，確實(shí)沒有C語言編譯環(huán)境gcc

:~$ apt-get install gcc 
E: Could not open lock file /var/lib/dpkg/lock-frontend - open (13: Permission denied)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?
:~$ sudo apt-get install gcc 
[sudo] password for alice: 
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done

用apt命令配置gcc環(huán)境apt-get install gcc ，首次嘗試未能成功，因?yàn)闆]有管理員權(quán)限，加上sudo， sudo apt-get****install gcc 再次嘗試，可以看到成功安裝。

:~$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/11/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu

至此，gcc環(huán)境配置成功。編寫一個C語言程序測試

#include < stdio.h >


int main(){
    printf("hello world!n");
    return 0;
}

測試文件test.c放在Document下面，經(jīng)過編譯gcc test.c 、運(yùn)行./a. out ，成功輸出“hello world！”

:~/Documents$ vi test.c
:~/Documents$ gcc test.c 
:~/Documents$ ls
a.out  test.c
:~/Documents$ ./a.out 
hello world!

配置Makefile

Makefile可以很好地管理C語言程序，Makefile的配置與gcc類似。

:~$ make -v
Command 'make' not found, but can be installed with:
sudo apt install make        # version 4.3-4.1build1, or
sudo apt install make-guile  # version 4.3-4.1build1

查看系統(tǒng)make -v，確實(shí)沒有make環(huán)境，現(xiàn)在配置該環(huán)境sudo apt-get install make

:~$ sudo apt-get install make
[sudo] password for alice: 
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Suggested packages:
  make-doc
The following NEW packages will be installed:
  make

再次查看，make環(huán)境配置完成

:~$ make -v
GNU Make 4.3
Built for x86_64-pc-linux-gnu
Copyright (C) 1988-2020 Free Software Foundation, Inc.

利用上述C語言程序，測試makefile，在Makefile文件中，寫入下面的代碼（其中Makefile首字母大寫，沒有后綴名）

test : test.o
  gcc -o test test.o


test.o : test.c
  gcc -c -o test.o test.c


clean :
  rm -f main test.o

每一行命令的gcc前面，一定是Tab鍵，不是空格，否則編譯make報錯。

:~/Documents$ make
gcc -c -o test.o test.c
gcc -o test test.o
:~/Documents$ ./test 
hello world!
:~/Documents$ ls
a.out  Makefile  test  test.c  test.o

經(jīng)過編譯make、運(yùn)行./test ，仍然可以正確輸出。