Linux Socket Programming by Example

Appendix B. Socket-Related Structures Reference

Socket Address Structures

sockaddr

#include <sys/socket.h>

struct sockaddr {
    sa_family_t  sa_family;    /* Address Family */
    char         sa_data[14];  /* Address data.  */
};

sockaddr_un

#include <sys/un.h>

struct sockaddr_un {
    sa_family_t  sun_family;   /* Address Family */
    char         sun_path[108]; /* Pathname */
};

sockaddr_in and in_addr

#include <netinet/in.h>

struct sockaddr_in {
    sa_family_t    sin_family; /* Address Family */
    uint16_t       sin_port;   /* Port number */
    struct in_addr sin_addr;   /* Internet address */
    unsigned char  sin_zero[8];/* Pad bytes */
};

struct in_addr {
    uint32_t       s_addr;     /* Internet address */

};

Special IPv4 Addresses

 adr.sin_addr.s_addr = ntohl(INADDR_ANY); adr.sin_addr.s_addr = ntohl(INADDR_LOOPBACK); ...