| lwIP
    2.1.2
    Lightweight IP stack | 
#include "lwip/arch.h"| Macros | |
| #define | IP_HDR_GET_VERSION(ptr) ((*(u8_t*)(ptr)) >> 4) | 
IP protocol definitions
| #define IP_HDR_GET_VERSION | ( | ptr | ) | ((*(u8_t*)(ptr)) >> 4) | 
This operates on a void* by loading the first byte