unp #5 (reading notes) (decralations)

#include <sys/types.h>
#include <sys/socket.h>
ssize_t send(int sockfd, const void* buf, size_t len, int flags);
ssize_t sendto(int sockfd, const void* buf, size_t len, int flags,
               const struct sockaddr* dest_addr, socklen_t addrlen);
ssize_t sendmsg(int sockfd, const struct msghdr* msg, int flags);

ssize_t recv(int sockfd, void* buf, size_t len, int flags);
ssize_t recvfrom(int sockfd, void* buf, size_t len, int flags, 
                 struct sockaddr* src_addr, socklen_t *addrlen);
ssize_t recvmsg(int sockfd, struct msghdr* msg, int flags);

struct msghdr {
  void         *msg_name;      /* optional address */
  socklen_t     msg_namelen;   /* size of address */
  struct iovec *msg_iov;       /* scatter/gather array */
  size_t        msg_iovlen;    /* # elements in msg_iov */
  void         *msg_control;   /* ancillary data, see below */
  size_t        msg_control;   /* ancillary data buffer len */
  int           msg_flags;     /* flags on received message */
};
  

#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
int getaddrinfo(const char* node, const char* service, 
                const struct addrinfo* hints, struct addrinfo** res);
void freeaddrinfo(struct addrinfo *res);
const char* gai_sterror(int errcode);

struct addrinfo {
  int             ai_flags;
  int             ai_family;
  int             ai_socktype;
  int             ai_protocol;
  socklen_t       ai_addrlen;
  struct sockaddr *ai_addr;
  char            *ai_canonname;
  struct addrinfo *ai_next;
};