#define MAXLINE 250

/* 
 *  Without "packed" the compiler will insert 
 *   padding into the struct. Remove it and 
 *   see what happens; printf( "%p %p\n", &req.pow, &req.num )
 *   will show you what the pointer values are.
 */    

struct request {
     uint8_t  pow;
     uint32_t num;
} __attribute__((packed));

struct response {
     uint8_t  status;
     uint32_t result;
     uint16_t len;
     char     str[MAXLINE];
} __attribute__((packed));