Sending Commands and Responses
LEADTOOLS provides a number of functions that allow you to send commands and responses between a local and a remote computer. This provides a means of using a "super computer" to store and process large numbers of images, while using a smaller, remote computer to send commands indicating which process to perform and which image to use.
In order to receive commands, an INETCOMMANDCALLBACK function should be set using the L_InetSetCommandCallback function, on the computer that will be receiving commands. If an INETCOMMANDCALLBACK function is not set, the INETCALLBACK function will be used by default for receiving commands. INETCALLBACK is not suitable for handling command parameters and extra data, so it is best to set an INETCOMMANDCALLBACK function. The supported command functions include the following:
When a computer receives a command, the INETCOMMANDCALLBACK function is called. The computer that receives the command should then send a response to the computer that sent the command. The supported response functions include the following:
To receive responses, the computer that sent the original command should also set an INETRESPONSECALLBACK function using L_InetSetResponseCallback.
While the L_InetSendLoadCmd, L_InetSendLoadRsp, L_InetSendSaveCmd, L_InetSendSaveRsp, etc. provide standard image processing commands and responses, the L_InetSendCmd and L_InetSendRsp functions provide a means of creating user-defined commands and responses. These commands and responses may require sending extra data, in the form of a packet, along with the command or the response. LEADTOOLS provides the following functions for creating and freeing packets: L_InetCreatePacket, L_InetCreatePacketFromParams and L_InetFreePacket. For a diagram of a client server set-up for sending commands and responses, refer to A Client-Server Diagram: Sending Commands and Responses.