open_socket_acceptT_open_socket_acceptOpenSocketAcceptOpenSocketAcceptopen_socket_accept (Operator)

Name

open_socket_acceptT_open_socket_acceptOpenSocketAcceptOpenSocketAcceptopen_socket_accept — Open a socket that accepts connection requests.

Signature

Description

open_socket_acceptopen_socket_acceptOpenSocketAcceptOpenSocketAcceptOpenSocketAcceptopen_socket_accept 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 PortPortPortPortportport.

It is possible to specify a PortPortPortPortportport of 0, triggering implementation-defined behavior. On most operating systems, using a port number of 0 instructs the operating system to choose a free port randomly.

The following parameters can be set for GenParamNameGenParamNameGenParamNameGenParamNamegenParamNamegen_param_name.

'protocol'"protocol""protocol""protocol""protocol""protocol":

Specifies the protocol to be used. The 'HALCON'"HALCON""HALCON""HALCON""HALCON""HALCON" protocol without a specific address family, will use IPv4 or IPv6 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""HALCON4" designates a HALCON connection over IPv4. Possible values for a generic socket communication are 'UDP'"UDP""UDP""UDP""UDP""UDP" and 'TCP'"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_dataSendDataSendDataSendDatasend_data and receive_datareceive_dataReceiveDataReceiveDataReceiveDatareceive_data only.

Default: 'HALCON'"HALCON""HALCON""HALCON""HALCON""HALCON"

'adress'"adress""adress""adress""adress""adress":

Instructs 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""localhost" would instruct the socket to accept only connections addressed to the address 'localhost'"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""127.0.0.1".

'timeout'"timeout""timeout""timeout""timeout""timeout":

Sets a timeout for this socket. The timeout is given in seconds or as the string 'infinite'"infinite""infinite""infinite""infinite""infinite". It is used especially as timeout and waiting mode in a following socket_accept_connectsocket_accept_connectSocketAcceptConnectSocketAcceptConnectSocketAcceptConnectsocket_accept_connect call with the parameter WaitWaitWaitWaitwaitwait set to 'auto'"auto""auto""auto""auto""auto".

'string_encoding'"string_encoding""string_encoding""string_encoding""string_encoding""string_encoding":

Sets the string encoding that is expected when sending and receiving strings with this socket. It is used for send_tuplesend_tupleSendTupleSendTupleSendTuplesend_tuple and receive_tuplereceive_tupleReceiveTupleReceiveTupleReceiveTuplereceive_tuple as well as send_datasend_dataSendDataSendDataSendDatasend_data and receive_datareceive_dataReceiveDataReceiveDataReceiveDatareceive_data. When the protocol 'HALCON'"HALCON""HALCON""HALCON""HALCON""HALCON" is used, the setting only has effect on connections to HALCON versions prior to 18.11. If the connection partner is detected to have HALCON version 18.11 or newer, UTF-8 is used to encode tuples.

'reuseaddr'"reuseaddr""reuseaddr""reuseaddr""reuseaddr""reuseaddr":

Controls the setting of the socket option SO_REUSEADDR. When 'reuseaddr'"reuseaddr""reuseaddr""reuseaddr""reuseaddr""reuseaddr" is set to 'false'"false""false""false""false""false", SO_REUSEADDR will not be set. On Windows Systems, conflicting access on a single port will only be detected, when 'reuseaddr'"reuseaddr""reuseaddr""reuseaddr""reuseaddr""reuseaddr" is set to 'false'"false""false""false""false""false".

Default: 'true'"true""true""true""true""true"

'tls_enable'"tls_enable""tls_enable""tls_enable""tls_enable""tls_enable":

Controls the use of Transport Layer Security (TLS) for the new Socket. When 'tls_enable'"tls_enable""tls_enable""tls_enable""tls_enable""tls_enable" is set to 'true'"true""true""true""true""true", the created socket will accept TLS secured connections only. Furthermore, both generic parameters 'tls_private_key'"tls_private_key""tls_private_key""tls_private_key""tls_private_key""tls_private_key" and 'tls_certificate'"tls_certificate""tls_certificate""tls_certificate""tls_certificate""tls_certificate" must be set, each with a path to the private certificate key and the path to the public server certificate. Private key and server certificate must be provided in PEM-format.

Default: 'false'"false""false""false""false""false"

The accepting socket is returned in AcceptingSocketAcceptingSocketAcceptingSocketAcceptingSocketacceptingSocketaccepting_socket. open_socket_acceptopen_socket_acceptOpenSocketAcceptOpenSocketAcceptOpenSocketAcceptopen_socket_accept returns immediately without waiting for a request from another process, which must be initiated by calling open_socket_connectopen_socket_connectOpenSocketConnectOpenSocketConnectOpenSocketConnectopen_socket_connect. This allows multiple other processes to connect to the particular HALCON process that calls open_socket_acceptopen_socket_acceptOpenSocketAcceptOpenSocketAcceptOpenSocketAcceptopen_socket_accept. To accept an incoming 'HALCON'"HALCON""HALCON""HALCON""HALCON""HALCON" or 'TCP'"TCP""TCP""TCP""TCP""TCP" connection request, socket_accept_connectsocket_accept_connectSocketAcceptConnectSocketAcceptConnectSocketAcceptConnectsocket_accept_connect 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_connectSocketAcceptConnectSocketAcceptConnectSocketAcceptConnectsocket_accept_connect

See also

open_socket_connectopen_socket_connectOpenSocketConnectOpenSocketConnectOpenSocketConnectopen_socket_connect, close_socketclose_socketCloseSocketCloseSocketCloseSocketclose_socket, get_socket_paramget_socket_paramGetSocketParamGetSocketParamGetSocketParamget_socket_param, set_socket_paramset_socket_paramSetSocketParamSetSocketParamSetSocketParamset_socket_param, send_imagesend_imageSendImageSendImageSendImagesend_image, receive_imagereceive_imageReceiveImageReceiveImageReceiveImagereceive_image, send_regionsend_regionSendRegionSendRegionSendRegionsend_region, receive_regionreceive_regionReceiveRegionReceiveRegionReceiveRegionreceive_region, send_tuplesend_tupleSendTupleSendTupleSendTuplesend_tuple, receive_tuplereceive_tupleReceiveTupleReceiveTupleReceiveTuplereceive_tuple, send_datasend_dataSendDataSendDataSendDatasend_data, receive_datareceive_dataReceiveDataReceiveDataReceiveDatareceive_data

Module

Foundation