Preparing Address Variables

Before your client process can make a request of the server process, you must establish the correct variables and collect the information you need about the server process.

Your server process needs to:

Declare socket address variables.
Get the pathname (character string) for the service you want to provide.

Your client process needs to:

Declare socket address variables.
Get the pathname (character string) for the service you want to use.

These activities are described next. Refer to the program example at the end of this chapter to see how these activities work together.

Declaring Socket Address Variables

You need to declare a variable of type struct sockaddr_un to use for the socket address for both processes. For example, the following declaration is used in the example server program:

struct sockaddr_un servaddr; /* server socket address */

sockaddr_un is a special case of sockaddr and is used with AF_UNIX address domain. The sockaddr_un address structure is defined in sys/un.h and consists of the following fields:

Field	Description
short sun_family	Specifies the address family and should always be set to AF_UNIX.
u_char sun_path[92]	Specifies the pathname to which the socket is bound or will be bound (e.g.: `/tmp/myserver`).

The server process only needs one address for its socket. Any process that knows the address of the server process can then send messages to it. Thus, your client process needs to know the address of the server socket. The client process will not need an address for its own socket, unless other processes need to refer to the client process.

Preparing Address Variables

Technical documentation

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Declaring Socket Address Variables