http://stackoverflow.com/questions/7423691/is-gets-officially-deprecated


Because it is impossible to tell without knowing the data in advance how many charac‐ters gets() will read, and because gets() will continue to store characters past the end of the buffer, it is extremely dangerous to use. It has been used to break computer security.



서비스로 manpage


ECURITY CONSIDERATIONS

     The gets() function cannot be used securely.  Because of its lack of

     bounds checking, and the inability for the calling program to reliably

     determine the length of the next incoming line, the use of this function

     enables malicious users to arbitrarily change a running program's func-

     tionality through a buffer overflow attack.  It is strongly suggested

     that the fgets() function be used in all cases.  (See the FSA.)


한마디로 요약하면 컴퓨터를 씹창 내고 싶으면 gets()를 쓰면 된다는거군...