A positive number or
A positive number or
One of the keywords
:both. The default value is
socket-stream implements a buffered stream connected to a socket. The socket handle, specified by
:socket, and the direction, specified by
:direction, must be passed for a meaningful stream to be constructed. Common Lisp input functions such as
read-char will see
end-of-file if the other end of the socket is closed.
:element-type initarg determines the expected element type of the stream traffic. However, stream input and output functions for character and binary data generally work in the obvious way on a
socket-stream with any of the allowed values of element-type. For example,
read-sequence can be called with a string buffer and a binary
socket-stream: the character data is constructed from the input as if by
write-sequence can be called with a string buffer and a binary
socket-stream: the output is converted from the character data as if by
char-code. Also, 8-bit binary data can be read and written to a
The read-timeout property is intended for use when a socket connection might hang during a call to any Common Lisp input function. The read-timeout can be set by make-instance or by open-tcp-stream. It can also be modified by
(setf stream:stream-read-timeout). When read-timeout is
nil, there is no timeout during reads and the call may hang. When read-timeout is not
nil, and there is no input from the socket for more than read-timeout seconds, any reading function returns
end-of-file. The read-timeout does not limit the time inside
read, but the time between successful extractions of data from the socket. Therefore, if the reading needs several rounds it may take longer than read-timeout.
(setf stream:stream-read-timeout) on the stream while it is inside a read function has undefined effects. However, the setf function can be used between calls to read functions. The read-timeout property of a stream can be read by
:handshake-timeout can be be supplied to create and configure socket streams with SSL processing. See Keyword arguments for use with SSL for more details.
If there is a non-local exit while initializing the
socket-stream (the most common reason being a SSL handshake failure when using SSL), then the stream will be closed. This will cause the socket to be closed as well.
cl:read-charand so on) can also wait properly. You can also use process-wait and similar functions with
cl:listenin the wait-function, but you will need to use with-noticed-socket-stream.
socket-streamis normally a socket object in the operating system sense. On Unix and Microsoft Windows it is an integer corresponding to a socket as returned from the C functions socket and accept. It can also be a Java socket object, see Socket streams with Java sockets and SSL on Android for details.
(setf socket-steam-socket)can be used to set the socket object in the stream, and can also set it to
nil. When there is already a socket in the stream,
(setf socket-steam-socket)closes it before setting the slot to the new socket. The function replace-socket-stream-socket can be used to set the socket without closing the old one.
LispWorks User Guide and Reference Manual - 20 Sep 2017