Direct return codes

When using the Harlequin Direct API, each function can return a subset of the following codes, but will always return 0 for successful operation.

Index	Return code suffix	Meaning
`0`	`Success`	The command was successful.
`1`	`InvalidArgument`	One or more of the given arguments was invalid (for example, empty/null.)
`2`	`UnknownError`	An unknown error occurred.
`3`	`CPlusPlusException`	A C++ exception was thrown.
`4`	`UnrecognizedCommand`	The given command was not recognized.
`5`	`NoActivePrintRun`	The command given could not execute, as no print run is active.
`6`	`PrintRunActive`	The command given could not execute, as a print run is active.
`7`	`FailedToLoadConfigFile`	The given config file could not be opened.
`8`	`JobFileNotFound`	The given file argument was not found at the specified path.
`9`	`InvalidConfig`	The given config file was invalid. This includes bad JSON syntax, wrongly typed fields, invalid directories specified within the config, or bad combinations of values (for example, enabling both Continuous and Mixed mode).
`10`	`InvalidPassword`	The password was invalid for the given licence.
`11`	`InvalidLicence`	The licence string or licence settings were invalid (for example. the RIP-count setting is too high for the specified licence).
`12`	`LicenceAlreadySet`	Could not set the licence because a licence was already set.
`13`	`NoConnection`	The command could not be sent as there was no socket connection.
`14`	`PluginFailedToLoad`	Failed to load a plugin; it may not exist at the specified path.
`15`	`PrintRunBusy`	The action could not be executed, as the active print run was still processing one or more jobs.
`16`	`InstanceNotFound`	The specified Harlequin Direct instance was not found.
`17`	`ApiAlreadyShutDown`	The API was already shut down when trying to issue a shutdown.
`18`	`ApiAlreadyActive`	The API was already active when trying to activate it.
`19`	`InvalidSocketInterfaceOperation`	The socket interface operation failed.
`20`	`SocketInterfaceAlreadyStarted`	The socket interface was already started when trying to start it.
`21`	`InvalidJobID`	The given job ID does not point to an existing job.
`22`	`BadClripDirectory`	The specified scalable RIP directory was not a directory.
`23`	`BadOutputDirectory`	The specified output directory for the scalable RIP was either unspecified or not a directory.
`24`	`ScalableRipNotFound`	The scalable RIP was not found in the specified directory.
`25`	`ZeroNumberOfRips`	The number of RIPs specified for the scalable RIP was zero.
`26`	`BadSpdDirectory`	The specified ScreenPro Direct directory was not a directory.
`27`	`ScreenProDirectNotFound`	ScreenPro Direct was not found in the specified directory.
`28`	`SPDConfigFileNotFound`	The specified ScreenPro Direct config file was not found.
`29`	`DuplicateScreenProDirectInstance`	A ScreenPro Direct instance already exists with the given ID.
`30`	`InvalidScreenProDirectOperation`	The issued command cannot be executed in ScreenPro Direct's current state (for example, attempted to start when already active).
`31`	`ScreenProDirectOperationFailed`	A ScreenPro Direct command was issued, and it returned with a failure code.
`32`	`PipelineStatusError`	An error occurred while fetching the pipeline status.
`33`	`InvalidSPDStatusTransition`	Could not transition ScreenPro Direct to the given status.
`34`	`InvalidPlaneNumber`	The given plane number argument to the `JobXmlSerializer` was invalid. This happens when attempting to set plane parameters of a plane that already exists, or adding a filename to a plane number that doesn't exist.
`35`	`InvalidScreenDirectory`	The given screen directory does not exist or is not empty.
`36`	`InvalidFilename`	The given file name does not exist.
`37`	`DuplicateHarlequinDirectInstance`	A Harlequin Direct instance already exists with the given ID.
`38`	`FailedToRegisterHandler`	An event handler failed to register.
`39`	`HeartbeatActive`	Could not execute the command because a heartbeat was already active.
`40`	`NoHeartbeatActive`	No heartbeat is active to carry out the given command.
`41`	`ResponseTimeout`	The Harlequin Direct socket timed out while expecting a response.
`42`	`ResultTimeout`	The Harlequin Direct socket timed out while expecting a result.
`43`	`FailedToSendData`	Data failed to send over the socket.
`44`	`ConnectionFailed`	Failed to establish a connection to a socket.
`45`	`InvalidJson`	The given JSON file was invalid. This error code is separate from `InvalidConfig` in that it only concerns JSON files that are not configs (for example. JSON metadata for sprites). The same conditions apply for bad syntax, bad value formatting, wrongly typed fields, and so on.
`46`	`InvalidOperation`	The command interface has already started.
`47`	`ScalableRipFailedToStart`	The scalable RIP has failed to start.
`48`	`PluginCommandFailed`	The named plugin is invalid/does not exist, the command is invalid, or the result is zero.