Setting The Server Up To Wait For Connection Requests - HP Rp3440-4 - 9000 - 0 MB RAM Programmer's Manual

Using UNIX Domain Stream Sockets
Writing the Server Process
Setting the Server Up to Wait for Connection
Requests
Once your server process has an address bound to it, it must call listen
to set up a queue that accepts incoming connection requests. The server
process then monitors the queue for requests (using select(2) or
accept ). The server process cannot respond to a connection request
until it has executed listen. listen and its parameters are described
in the following table.
Include files: none
System call:
listen(s, backlog)
int s, backlog;
Parameter
s socket descriptor of local
socket
backlog preferred maximum
number of connection
requests in the queue at
any time
Function result: 0 if listen is successful, –1 if failure occurs.
Example:
listen (ls, 5);
backlog is the preferred number of unaccepted incoming connections
allowed at a given time. The actual number may be greater than the
specified backlog. When the queue is full, further connection requests
are rejected.
A backlog of 0 specifies only 1 pending connection can exist at any given
time. SOMAXCONN is defined in <sys/socket.h>. The current
default setting is 20, but may change in future releases.
When to Set Server Up to Listen
The server process should set up server to listen after socket is created
and bound and before the server can respond to connection requests.
Refer to the listen(2) man page for more information on listen.
130
Description of
Contents
INPUT Value
server socket's
descriptor
size of queue (between 0
and SOMAXCONN)
Chapter 6