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SPR Script Language
TCP.Close
Closes an open TCP client connection.
Intention
The TCP.Close command terminates an active TCP client connection identified by its socket handle ($$HND). It is crucial to close connections when they are no longer needed to release system resources. After a connection is closed, the handle becomes invalid and cannot be used for further network operations.
Illustration
[Client Script] [Network Server]
| |
| TCP/IP Connection |
TCP.Close <---------- (Socket HND) ---------->
(Socket HND)
Syntax
TCP.Close|$$HND
Parameter Explanation
P1 - $$HND - (Variable, Numeric, Required)
The socket handle of the open TCP connection to be closed, obtained from TCP.Open.
Return Value (on Stack)
The command pushes 1 onto the stack to indicate that the close operation was attempted.
Examples
'***********************************
' TCP.Close - Sample 1: Close a TCP Connection
'***********************************
TCP.Open|127.0.0.1|5556
POP.$$HND
JIZ.$$HND|Error_Handler
' ... send/receive data ...
TCP.Close|$$HND
POP.$$CLOSE_STATUS ' Get the status (always 1)
PRT.Connection closed.
Remarks
- It is good practice to close all open TCP connections when they are no longer needed to free system resources.
- Attempting to use a closed handle will result in an error.
- The return value (1) indicates that the close operation was initiated, not necessarily that the remote end has acknowledged the close.
See also:
• TCP.Open
• TCP.Send
• TCP.Recv