SOCKETCLOSE

Action

Closes a socket connection.

 

 

Syntax

SOCKETCLOSE socket [ , prm]

 

 

Remarks

Socket

The socket number you want to close in the range of 0-3 (0-7 for W5200/W5300). When the socket is already closed, no action will be performed.

Prm

An optional parameter to change the behavior of the CloseSocket statement. The following values are possible : • 0 - The code will behave as if no parameter has been set. • 1 - In normal cases, there is a test to see if all data written to the chip has been sent. When you set bit 0 (value of 1) , this test is not performed. • 2 - In normal cases, there is a test to see if the socket is actually closed after the command has been given to the chip. When it is not closed, you can not re-use the socket. The statement will block program execution however and you could test at a later time if the connection has been closed.   You may combine the values. So 3 will combine parameter value 1 and 2. It is advised to use option value 1 with care.

 

You must close a socket when you receive the SOCK_CLOSE_WAIT status.

You may also close a socket if that is needed by your protocol.

You will receive a SOCK_CLOSE_WAIT status when the server closes the connection.

 

When you use CloseSocket you actively close the connection.

Note that it is not needed to wait for a SOCK_CLOSE_WAIT message in order to close a socket connection.

 

After you have closed the connection, you need to use GetSocket in order to use the socket number again.

 

In normal conditions, without using the optional parameter, the statement can block your code for a short or longer time, depending on the connection speed.

 

The CLOSESOCKET statement is equivalent with SOCKETCLOSE.

 

 

See also

CONFIG TCPIP, GETSOCKET , SOCKETCONNECT, SOCKETSTAT , TCPWRITE, TCPWRITESTR, TCPREAD, SOCKETLISTEN ,SOCKETDISCONNECT

 

 

Example

'-----------------------------------------------------------------------------------------
'name : clienttest.bas
'copyright : (c) 1995-2005, MCS Electronics
'purpose : start the easytcp.exe program and listen to port 5000
'micro : Mega161
'suited for demo : no
'commercial addon needed : yes
'-----------------------------------------------------------------------------------------
 
$regfile = "M161def.dat"
$crystal = 4000000
$baud = 19200
$hwstack = 40 ' default use 40 for the hardware stack
$swstack = 40 ' default use 40 for the SW stack
$framesize = 64 ' default use64 for the frame space
 
Const Sock_stream = $01 ' Tcp
Const Sock_dgram = $02 ' Udp
Const Sock_ipl_raw = $03 ' Ip Layer Raw Sock
Const Sock_macl_raw = $04 ' Mac Layer Raw Sock
Const Sel_control = 0 ' Confirm Socket Status
Const Sel_send = 1 ' Confirm Tx Free Buffer Size
Const Sel_recv = 2 ' Confirm Rx Data Size
 
'socket status
Const Sock_closed = $00 ' Status Of Connection Closed
Const Sock_arp = $01 ' Status Of Arp
Const Sock_listen = $02 ' Status Of Waiting For Tcp Connection Setup
Const Sock_synsent = $03 ' Status Of Setting Up Tcp Connection
Const Sock_synsent_ack = $04 ' Status Of Setting Up Tcp Connection
Const Sock_synrecv = $05 ' Status Of Setting Up Tcp Connection
Const Sock_established = $06 ' Status Of Tcp Connection Established
Const Sock_close_wait = $07 ' Status Of Closing Tcp Connection
Const Sock_last_ack = $08 ' Status Of Closing Tcp Connection
Const Sock_fin_wait1 = $09 ' Status Of Closing Tcp Connection
Const Sock_fin_wait2 = $0a ' Status Of Closing Tcp Connection
Const Sock_closing = $0b ' Status Of Closing Tcp Connection
Const Sock_time_wait = $0c ' Status Of Closing Tcp Connection
Const Sock_reset = $0d ' Status Of Closing Tcp Connection
Const Sock_init = $0e ' Status Of Socket Initialization
Const Sock_udp = $0f ' Status Of Udp
Const Sock_raw = $10 ' Status of IP RAW
 
 
 
$lib "tcpip.lbx" ' specify the tcpip library
Print "Init , set IP to 192.168.0.8" ' display a message
Enable Interrupts ' before we use config tcpip , we need to enable the interrupts
Config Tcpip = Int0 , Mac = 12.128.12.34.56.78 , Ip = 192.168.0.8 , Submask = 255.255.255.0 , Gateway = 0.0.0.0 , Localport = 1000 , Tx = $55 , Rx = $55
 
'Use the line below if you have a gate way
'Config Tcpip = Int0 , Mac = 12.128.12.34.56.78 , Ip = 192.168.0.8 , Submask = 255.255.255.0 , Gateway = 192.168.0.1 , Localport = 1000 , Tx = $55 , Rx = $55
 
Dim Bclient As Byte ' socket number
Dim Idx As Byte
Dim Result As Word ' result
Dim S As String * 80
 
For Idx = 0 To 3 ' for all sockets
Bclient = Getsocket(idx , Sock_stream , 0 , 0) ' get socket for client mode, specify port 0 so loal_port is used
Print "Local port : " ; Local_port ' print local port that was used
Print "Socket " ; Idx ; " " ; Bclient
Result = Socketconnect(idx , 192.168.0.3 , 5000) ' connect to easytcpip.exe server
Print "Result " ; Result
Next
 
Do
 
If Ischarwaiting() <> 0 Then ' is there a key waiting in the uart?
 Bclient = Waitkey() ' get the key
 If Bclient = 27 Then
 Input "Enter string to send " , S ' send WHO , TIME or EXIT
 For Idx = 0 To 3
 Result = Tcpwritestr(idx , S , 255)
 Next
 End If
End If
 
For Idx = 0 To 3
 Result = Socketstat(idx , 0) ' get status
 Select Case Result
 Case Sock_established
 Result = Socketstat(idx , Sel_recv) ' get number of bytes waiting
 If Result > 0 Then
 Do
 Result = Tcpread(idx , S)
 Print "Data from server: " ; Idx ; " " ; S
 Loop Until Result = 0
 End If
 Case Sock_close_wait
 Print "close_wait"
 Closesocket Idx
 Case Sock_closed
 'Print "closed"
 End Select
Next
Loop
End

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