gets into char *str without malloc, no segfault?

Question

I\'ve just compiled this C program using Cygwin\'s gcc:

#include 

void main (){
    char *str;
    gets(str);
    printf(\"%s\",str);
}
         


        

Answer 1

Access memory region pointed to by uninitialized pointer is undefined behavior, it could crash, it also could look like working normally. In a word, you cannot predict its behavior.

How come I'm not getting a segmentation fault?

Uninitialized pointer has an undetermined value, it could point to anywhere, if it points to some big enough writable region accidently, that program will "work" normally.