Underhanded C: Post your blurbs!

Underhanded C is the art of writing code that obviously does one thing - while actually doing something slightly different.


I will offer today’s “I spent too long debugging this…” example.

uint64_t a = 0x8000;
bool flag = false;
uint64_t c = a + flag ? 0 : 4;
printf("c: %lx\n", c);

What’s the value of c?