Socket structs

addrinfo

struct addrinfo {

 int ai_flags;          // AI_PASSIVE, AI_CANONNAME, etc.
 int ai_family;         // AF_INET, AF_INET6, AF_UNSPEC
 int ai_socktype;       // SOCK_STREAM, SOCK_DGRAM
 int ai_protocol;       // use 0 for "any"
 size_t ai_addrlen;     // size of ai_addr in bytes
 struct sockaddr *ai_addr; // struct sockaddr_in or _in6
 char *ai_canonname;    // full canonical hostname
 struct addrinfo *ai_next; // linked list, next node

};