Reads data from a socket connection.

connection—A socket handle (usually returned by either SOCKET_ACCEPT or SOCKET_CONNECT).

data—A pre-allocated byte array to read into.

None.

nbytes—The number of bytes read from the socket or a negative value indicating an error.

This function can be used in both client and server programs. If used in a client program, it retrieves data sent (using SOCKET_WRITE) from the server. If used in a server program, it retrieves data sent from the client.

Before calling SOCKET_READ, you must initialize data to be a byte array of sufficient size to hold the data sent from the client. It is up to the programmer to convert the data in the byte array into whatever form the server or client expects to process. PV‑WAVE provides several routines for converting data from one type to another, including BYTE, BYTEORDER, COMPLEX, DOUBLE, FLOAT, LONG, and STRING.

In this example, a client program uses SOCKET_READ to retrieve a byte array sent from the server. Note that the STRING function is used to convert the byte array to a string before the data is printed.

PRO CLIENT

   host = 'localhost'

   port = 1500

   socket = SOCKET_CONNECT(host,port)

   IF socket EQ -1 OR socket EQ -2 THEN BEGIN

      PRINT, 'SOCKET_CONNECT failed with return code: ', socket

      RETURN

   ENDIF

   data = BYTARR(15)

   nbytes = SOCKET_READ(socket,data)

   PRINT, 'CLIENT received: ', STRING(data)

   SOCKET_CLOSE, socket

END

SOCKET_WRITE

For more detailed information on using the socket routines, see the PV‑WAVE Application Developer’s Guide.