Command TCP_State

4D Internet Commands

TCP_State

version 6.5


TCP_State (tcp_ID; statusCode) Integer

ParameterTypeDescription
tcp_IDLongintReference to an open TCP
statusCodeIntegerTCP status code

Function result Integer Error Code

Description

The TCP_State command returns an integer value corresponding to the state of a particular TCP connection.

tcp_ID is a long integer reference to an open TCP session as established with either the TCP_Open or TCP_Listen command.

statusCode is an integer variable returned which corresponds to one of the status codes below.

0Connection Closed
2Listening for an incoming connection
8Established

Example

This example assumes that a valid TCP connection has already been established and is identified by the Longint value assigned to the $tcp_id variable. In this example, a command is sent to a web server requesting a page of information and then a loop is entered to receive the results. Since web servers automatically close their connnections once they have performed their action, this example keeps receiving until the connection is dropped or an error occurs.

   C_LONGINT($tcp_id)
   C_INTEGER(vState;$err)
   C_TEXT($command;$buffer;$response)
   If (TCP_Send ($tcp_id;$command)=0)
      vState:=0
      Repeat
         $err:=TCP_Receive ($tcp_id;$buffer)
         $err:=TCP_State ($tcp_id;vState)
         $response:=$response+$buffer
      Until ((vState=0) | ($err#0))
   End if 

See Also

TCP_Listen, TCP_Open.