XPC Developer Information

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#Plugin Information

A Note on binaries: We keep the binaries for the plugin in version control to keep track of all of them across platforms. However, it is very hard to keep all of the binaries in sync all of the time. Therefore, develoepers working on any branch other than master are advised to always build the plugin before use to ensure that the binary includes all of the latest changes.

##Components The following components make up the X-Plane Connect plugin. All components are written in C++. In general, there is a one-to-one correspondence between the components described below and a header file bearing the same name.

###Data Manager The Data Manager component provides a wrapper around the XPLM data interface. This component provides two basic data interface mechanisms. The primary mechanism is the DREF scoped enumeration that names commonly used X-Plane datarefs. The DataManager class provides methods to get and set the value of these datarefs in a strongly typed manner. Secondly, the DataManager class provides weakly typed methods to set arbitrary datarefs by name using floating point values.

###Drawing The Drawing component provides functionality for rendering graphics in the X-Plane environment. Currently, this includes writing a single text string on the screen, and rendering a sequence of waypoints in the X-Plane world.

###Log The Log component facilitates the logging of information about what the XPC plugin is doing while it is running. Logging is accomplished through two methods. Other components can write to the XPC log either by calling Log::WriteLine to write a string to the log directly, or Log::FormatLine to write a formatted string to the log.

###Message & Message Handlers The messaging component handles commands sent to the plugin. The Message class is primarily a data object containing the message data. The MessageHandlers class contains the core functionality of the plugin. It contains methods to operate on commands, and logic to dispatch incoming messages to the appropriate handler.

###UDPSocket The UDPScocket component is a thin wrapper around the platform networking API. Its primary purpose is to abstract cross-platform differences.

#Network Information

#Client Information

#Troubleshooting The following topics have been identified as frequent obstacles to correct operation of the XPC plugin. If you are having an issue that is not covered here, or if the troubleshooting steps listed here do not resolve your issue, please let us know by opening an issue.

###Failing to read data By default, the XPC clients all set a read timeout of 100ms. This timeout should work well for systems where the client and plugin are running on the same machine, but it may be too aggressive for systems where the client is running on another machine, or in situations where X-Plane is running at a low frame-rate.

Troubleshooting steps:

• Increase the read timeout. This can be accomplished by calling the appropriate version of the client constructor or openUDP for all versions except the C client. For the C client, you can manually set the timeouts in in the aopenUDP function. For Windows users, you may also want to adjust the timeout for select in the readUDP function.
• Lower X-Plane graphics settings. X-Plane Connect is structured to run once per iterations of the X-Plane flight simulation loop. If X-Plane is running at a low frame-rate, it will increase the time it takes X-Plane Connect to respond to requests. You can view the current frame-rate by following the steps described here.