Index for Section 2

Alphabetical listing for L

Bottom of page

listen(2)
NAME
  listen - Listen for socket connections and limits the backlog of incoming
  connections

SYNOPSIS
  #include <sys/socket.h>

  int listen(
	  int socket,
	  int backlog );

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  listen(): XNS4.0, XNS5.0

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  socket
      Specifies the unique name for the socket.

  backlog
      Specifies the maximum number of outstanding connection requests.

DESCRIPTION
  The listen() function identifies the socket that receives the connections,
  marks the socket as accepting connections, and limits the number (backlog)
  of outstanding connection requests in the system queue.

  The maximum queue length (backlog) that the listen() function can specify
  is indicated by the somaxconn kernel attribute in the socket subsystem. Use
  the sysconfig -q socket somaxconn to obtain this value from the kernel. See
  sys_attrs_socket(5) for more information.

  The socket in use may require that the process have appropriate privileges
  to use the listen() function.

RETURN VALUES
  Upon successful completion, the listen() function returns a value of 0
  (zero). Otherwise, a value of -1 is returned and errno is set to indicate
  the error.

ERRORS
  If the listen() function fails, errno may be set to one of the following
  values:

  [EACCES]
      The requested address is protected and the current process does not
      have permission to access it.

  [EBADF]
      The socket parameter is not valid.

  [EDESTADDRREQ]
      The socket is not bound to a local address, and the protocol does not
      support listening on an unbound socket.

  [EINVAL]
      The socket is already connected; or the socket is shut down.

  [ENOBUFS]
      Insufficient resources are available in the system to complete the
      call.

  [ENOTSOCK]
      The socket parameter refers to a file, not a socket.

  [EOPNOTSUPP]
      The referenced socket is not a type that supports the listen()
      function.

SEE ALSO
  Functions: accept(2), connect(2), socket(2)

  Standards: standards(5)

  Network Programmer's Guide

Index for Section 2

Alphabetical listing for L

Top of page