The C specification (and C++, I believe) state that this the result is undefined. So the compiler can produce any result and still be "correct". I've never seen the spec for PHP, assuming there is one.

beg to differ, but C and C++ do not evaluate assignments to true. They evaluate to the rvalue. And yes, I just tried it using GCC. #include int x; int main() { if (x=0) { printf("assignments evaluate to true!\n"); } return 0; }