foo.cpp: In function 'void io::init()':
foo.cpp:12:49: error: 'fread_unlocked' was not declared in this scope
         T = S+fread_unlocked(B, 1, MAXBUF, stdin);
                                                 ^
foo.cpp: In function 'void io::output()':
foo.cpp:65:68: error: 'fwrite_unlocked' was not declared in this scope
  inline void output() {fwrite_unlocked(buff, 1, iter - buff, stdout), iter = buff;}
                                                                    ^