open_socket_acceptopen_socket_acceptOpenSocketAcceptOpenSocketAccept (Operator)

Name

open_socket_acceptopen_socket_acceptOpenSocketAcceptOpenSocketAccept — Open a socket that accepts connection requests.

Signature

Description

open_socket_acceptopen_socket_acceptOpenSocketAcceptOpenSocketAcceptOpenSocketAccept opens a socket that will accept incoming connection requests. This operator is the necessary first step in the establishment of a communication channel between two HALCON processes. The socket listens for incoming connection requests on the port number given by PortPortPortPortport.

The generic parameter 'protocol'"protocol""protocol""protocol""protocol" may be used to specify the protocol to be used. The default is the 'HALCON'"HALCON""HALCON""HALCON""HALCON" protocol without specific address family. Therefore, IPv4 or IPv6 will be used automatically depending on the network configuration of the computer. To use a specific address family a '4' or '6' (for IPv4 or IPv6, respectively) must be appended to the name of the protocol. For example, 'HALCON4'"HALCON4""HALCON4""HALCON4""HALCON4" designates a HALCON connection over IPv4. Possible values for a generic socket communication are 'UDP'"UDP""UDP""UDP""UDP" and 'TCP'"TCP""TCP""TCP""TCP" which also support appended '4' and '6'. Both communication partners must use the same protocol. To exchange data using generic sockets use send_datasend_dataSendDataSendDataSendData and receive_datareceive_dataReceiveDataReceiveDataReceiveData only.

The generic parameter 'address'"address""address""address""address" can be used to instruct the socket to accept only connection requests addressed to a specific address. This address is specified as either an IPv4 or IPv6 address in numerical form, or a hostname. For example, 'localhost'"localhost""localhost""localhost""localhost" would instruct the socket to accept only connections addressed to the address 'localhost'"localhost""localhost""localhost""localhost", which normally maps to the local loopback network interface '127.0.0.1'"127.0.0.1""127.0.0.1""127.0.0.1""127.0.0.1".

The generic parameter 'timeout'"timeout""timeout""timeout""timeout" can be used to set a timeout for this socket. The timeout is given in seconds or as the string 'infinite'"infinite""infinite""infinite""infinite". It is used especially as timeout and waiting mode in a following socket_accept_connectsocket_accept_connectSocketAcceptConnectSocketAcceptConnectSocketAcceptConnect call with the parameter Wait set to 'auto'"auto""auto""auto""auto".

The accepting socket is returned in AcceptingSocketAcceptingSocketAcceptingSocketAcceptingSocketacceptingSocket. open_socket_acceptopen_socket_acceptOpenSocketAcceptOpenSocketAcceptOpenSocketAccept returns immediately without waiting for a request from another process, which must be initiated by calling open_socket_connectopen_socket_connectOpenSocketConnectOpenSocketConnectOpenSocketConnect. This allows multiple other processes to connect to the particular HALCON process that calls open_socket_acceptopen_socket_acceptOpenSocketAcceptOpenSocketAcceptOpenSocketAccept. To accept an incoming 'HALCON'"HALCON""HALCON""HALCON""HALCON" or 'TCP'"TCP""TCP""TCP""TCP" connection request, socket_accept_connectsocket_accept_connectSocketAcceptConnectSocketAcceptConnectSocketAcceptConnect must be called to obtain a socket for the final communication.

Execution Information

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Processed without parallelization.

This operator returns a handle. Note that the state of an instance of this handle type may be changed by specific operators even though the handle is used as an input parameter by those operators.

Parameters

Example (HDevelop)

* Process 1
dev_set_colored (12)
open_socket_accept (3000, [], [], AcceptingSocket)
* Busy wait for an incoming connection
dev_error_var (Error, 1)
dev_set_check ('~give_error')
OpenStatus := 5
while (OpenStatus != 2)
    socket_accept_connect (AcceptingSocket, 'false', Socket)
    OpenStatus := Error
    wait_seconds (0.2)
endwhile
dev_set_check ('give_error')
* Connection established
receive_image (Image, Socket)
threshold (Image, Region, 0, 63)
send_region (Region, Socket)
receive_region (ConnectedRegions, Socket)
area_center (ConnectedRegions, Area, Row, Column)
send_tuple (Socket, Area)
send_tuple (Socket, Row)
send_tuple (Socket, Column)
close_socket (Socket)
close_socket (AcceptingSocket)

* Process 2
dev_set_colored (12)
open_socket_connect ('localhost', 3000, [], [], Socket)
read_image (Image, 'fabrik')
send_image (Image, Socket)
receive_region (Region, Socket)
connection (Region, ConnectedRegions)
send_region (ConnectedRegions, Socket)
receive_tuple (Socket, Area)
receive_tuple (Socket, Row)
receive_tuple (Socket, Column)
close_socket (Socket)

Possible Successors

socket_accept_connectsocket_accept_connectSocketAcceptConnectSocketAcceptConnectSocketAcceptConnect

See also

open_socket_connectopen_socket_connectOpenSocketConnectOpenSocketConnectOpenSocketConnect, close_socketclose_socketCloseSocketCloseSocketCloseSocket, get_socket_paramget_socket_paramGetSocketParamGetSocketParamGetSocketParam, set_socket_paramset_socket_paramSetSocketParamSetSocketParamSetSocketParam, send_imagesend_imageSendImageSendImageSendImage, receive_imagereceive_imageReceiveImageReceiveImageReceiveImage, send_regionsend_regionSendRegionSendRegionSendRegion, receive_regionreceive_regionReceiveRegionReceiveRegionReceiveRegion, send_tuplesend_tupleSendTupleSendTupleSendTuple, receive_tuplereceive_tupleReceiveTupleReceiveTupleReceiveTuple, send_datasend_dataSendDataSendDataSendData, receive_datareceive_dataReceiveDataReceiveDataReceiveData

Module

Foundation