The RtdRMPClient Class

The RtdRMPClient object overrides some of the RMP handling routines of RtdRMP as well as adding specific methods relating to the receipt and forwarding of image data. It also implements the methods of the rtdrmpclient Tk widget. See rtdrmpclient(n) for more information on these.

Note that the unpacking of the data may also be a time-consuming process, and so the client forks to allow the parent process to continue processing RMP events while the image data is uncompressed. The mechanism used is slightly different to the server: the child process processes the data and puts it into shared memory before sending the image information to the rtdServer. It then raises a semaphore and exits. The parent process detects that the data has been forwarded and so flags that the client is ready to receive another image from the eavesdrop server.

The following are the most important of the RtdRMPClient methods:

processData(RMPEvent *) - called from the event handler when a message event is received, this routine calls a processing routine based on the contents of the message,
writeRawData(RMPEvent *) - called from processData() in the case that the message is made up of image data, this routine puts the incoming data into a local buffer,
writeShmData(char *) - unpacks and copies the image into shared memory ready for forwarding,
createRtdPacket() - creates the image information and forwards this to the rtdServer,
checkStatus() - called by the parent to detect whether the child process has completed,