Is gcc’s __attribute__((packed)) / #pragma pack unsafe?
Yes, __attribute__((packed)) is potentially unsafe on some systems. The symptom probably won’t show up on an x86, which just makes the problem more insidious; testing on x86 systems won’t reveal the problem. (On the x86, misaligned accesses are handled in hardware; if you dereference an int* pointer that points to an odd address, it will … Read more