You are confusing unsafe behavior with undefined behavior. He is not suggesting that a C compiler should prevent the above mistakes. He's suggesting that it sho

You are confusing unsafe behavior with undefined behavior. He is not suggesting that a C compiler should prevent the above mistakes. He's suggesting that it should document what code the compiler will emit in such cases. For example, - reading past the end of an array will always segfault the program immediately. or reading past the end of an array will return (arrayType)0 - signed integer types must overflow according to two's complement. A compiler may not assume that, for instance, (int)x < (int)x + 1 is always true. - uninitialized variables are zeroed out. That is, `int *x;` always produces a null pointer, `char y` always produces '0' - A compiler may not remove any statements where it determines such an optimization would not change the behavior of the program. See http://www.daemonology.net/blog/2014-09-04-how-to-zero-a-buffer.html http://www.daemonology.net/blog/2014-09-04-how-to-zero-a-buf... Such a compiler would accept and compile any C program, and the programmer (and any static analysis tools) would have a better idea of the behavior of the output program.