open_socket_accept — Open a socket that accepts connection requests.
open_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 Port.
The generic parameter 'protocol' may be used to specify the protocol to be used. The default is the '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' designates a HALCON connection over IPv4. Possible values for a generic socket communication are 'UDP' and 'TCP' which also support appended '4' and '6'. Both communication partners must use the same protocol. To exchange data using generic sockets use send_data and receive_data only.
The generic parameter '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' would instruct the socket to accept only connections addressed to the address 'localhost', which normally maps to the local loopback network interface '127.0.0.1'.
The generic parameter 'timeout' can be used to set a timeout for this socket. The timeout is given in seconds or as the string 'infinite'. It is used especially as timeout and waiting mode in a following socket_accept_connect call with the parameter Wait set to 'auto'.
The generic parameter 'reuseaddr' can be used to control the setting of the socket option SO_REUSEADDR. The default value is 'true'. When 'reuseaddr' is set to 'false', SO_REUSEADDR will not be set. On Windows Systems, conflicting access on a single port will only be detected, when 'reuseaddr' is set to 'false'.
The accepting socket is returned in AcceptingSocket. open_socket_accept returns immediately without waiting for a request from another process, which must be initiated by calling open_socket_connect. This allows multiple other processes to connect to the particular HALCON process that calls open_socket_accept. To accept an incoming 'HALCON' or 'TCP' connection request, socket_accept_connect must be called to obtain a socket for the final communication.
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.
Default value: 3000
Suggested values: 3000, 4570
Typical range of values: 1024 ≤ Port ≤ 65535
Minimum increment: 1
Recommended increment: 1
Names of the generic parameters that can be adjusted for the socket.
Default value: 
List of values: 'address', 'protocol', 'timeout'
Values of the generic parameters that can be adjusted for the socket.
Default value: 
Suggested values: 0, 3.0, 'infinite', 'HALCON', 'UDP', 'TCP', 'HALCON4', 'UDP4', 'TCP4', 'HALCON6', 'UDP6', 'TCP6'
* 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)
open_socket_connect, close_socket, get_socket_param, set_socket_param, send_image, receive_image, send_region, receive_region, send_tuple, receive_tuple, send_data, receive_data