/in/foo.cc: In function 'int mian()':
/in/foo.cc:8:1: warning: no return statement in function returning non-void [-Wreturn-type]
    8 | }
      | ^
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/Scrt1.o: in function `_start':
(.text+0x24): undefined reference to `main'
collect2: error: ld returned 1 exit status