Using A Wildcard Local Address - HP Rp3440-4 - 9000 - 0 MB RAM Programmer's Manual

Using Internet Datagram Sockets
Preparing Address Variables
When to Get Server's Socket Address
The server process should get the server's socket address before binding.
The client process should get the server's socket address before client
requests the service from the host. Refer to the getservent(3N) man
page for more information on getservbyname.

Using a Wildcard Local Address

Wildcard addressing simplifies local address binding. When an address
is assigned the value of INADDR_ANY, the host interprets the address
as any valid address. This means that the server process can receive on a
wildcard address and does not have to look up its own internet address.
For example, to bind a specific port address to a socket, but leave the
local internet address unspecified, the following source code could be
used:
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
...
struct sockaddr_in sin;
...
s = socket(AF_INET, SOCK_DGRAM, 0);
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;
sin.sin_port = MYPORT;
bind (s, &sin, sizeof(sin));
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