Giving a Socket a Name - bind()

#include <sys/types.h>

#include <sys/socket.h>

int bind(int s, struct sockaddr *name, int namelen)

Recall that, using socketpair(), sockets could only be shared between parent and child processes or children of the same parent. With a name attached to the socket, any process on the system can describe (and use) it.

In a call to bind(), s is the file descriptor for the socket, obtained from the call to socket(). name is a pointer to a structure of type sockaddr. If the address family is AF_UNIX (as specified when the socket is created), the structure is defined as follows:

struct sockaddr {

u_short sa_family;

char sa_data[14];

};

name.sa_family should be AF_UNIX. name.sa_data should contain up to 14 bytes of a file name which will be assigned to the socket. namelen gives the actual length of name, that is, the length of the initialized contents of the data structure.

A value of 0 is return on success. On failure, -1 is returned with errno describing the error.

Example:

struct sockaddr name;

int s;

name.sa_family = AF_UNIX;

strcpy(name.sa_data, "/tmp/sock");

if((s = socket(AF_UNIX, SOCK_STREAM, 0) < 0)

{

printf("socket create failure %dn", errno);

exit(0);

}

if (bind(s, &name, strlen(name.sa_data) +

sizeof(name.sa_family)) < 0)

printf("bind failure %dn", errno);