717 lines
29 KiB
C
717 lines
29 KiB
C
#ifndef _XPLMDataAccess_h_
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#define _XPLMDataAccess_h_
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/*
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* Copyright 2005-2012 Sandy Barbour and Ben Supnik All rights reserved. See
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* license.txt for usage. X-Plane SDK Version: 2.1.1
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*
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*/
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/***************************************************************************
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* XPLMDataAccess
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***************************************************************************/
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/*
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* The data access API gives you a generic, flexible, high performance way to
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* read and write data to and from X-Plane and other plug-ins. For example,
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* this API allows you to read and set the nav radios, get the plane location,
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* determine the current effective graphics frame rate, etc.
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*
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* The data access APIs are the way that you read and write data from the sim
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* as well as other plugins.
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*
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* The API works using opaque data references. A data reference is a source of
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* data; you do not know where it comes from, but once you have it you can
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* read the data quickly and possibly write it.
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*
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* Dataref Lookup
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* --------------
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*
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* Data references are identified by verbose, permanent string names; by
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* convention these names use path separates to form a hierarchy of datarefs,
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* e.g. (sim/cockpit/radios/nav1_freq_hz). The actual opaque numeric value of
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* the data reference, as returned by the XPLM API, is implementation defined
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* and changes each time X-Plane is launched; therefore you need to look up
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* the dataref by path every time your plugin runs.
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*
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* The task of looking up a data reference is relatively expensive; look up
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* your data references once based on the verbose path strings, and save the
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* opaque data reference value for the duration of your plugin's operation.
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* Reading and writing data references is relatively fast (the cost is
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* equivalent to two function calls through function pointers).
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*
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* X-Plane publishes over 4000 datarefs; a complete list may be found in the
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* reference section of the SDK online documentation (from the SDK home page,
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* choose Documentation).
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*
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* Dataref Types
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* -------------
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*
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* A note on typing: you must know the correct data type to read and write.
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* APIs are provided for reading and writing data in a number of ways. You can
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* also double check the data type for a data ref. Automatic type conversion
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* is not done for you.
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*
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* Dataref types are a set, e.g. a dataref can be more than one type. When
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* this happens, you can choose which API you want to use to read. For
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* example, it is not uncommon for a dataref to be of type float and double.
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* This means you can use either XPLMGetDatad or XPLMGetDataf to read it.
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*
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* Creating New Datarefs
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* ---------------------
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*
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* X-Plane provides datarefs that come with the sim, but plugins can also
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* create their own datarefs. A plugin creates a dataref by registering
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* function callbacks to read and write the dataref. The XPLM will call your
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* plugin each time some other plugin (or X-Plane) tries to read or write the
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* dataref. You must provide a read (and optional write) callback for each
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* data type you support.
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*
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* A note for plugins sharing data with other plugins: the load order of
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* plugins is not guaranteed. To make sure that every plugin publishing data
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* has published their data references before other plugins try to subscribe,
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* publish your data references in your start routine but resolve them the
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* first time your 'enable' routine is called, or the first time they are
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* needed in code.
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*
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* When a plugin that created a dataref is unloaded, it becomes "orphaned".
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* The dataref handle continues to be usable, but the dataref is not writable,
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* and reading it will always return 0 (or 0 items for arrays). If the plugin
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* is reloaded and re-registers the dataref, the handle becomes un-orphaned
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* and works again.
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*
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*/
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#include "XPLMDefs.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/***************************************************************************
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* READING AND WRITING DATA
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***************************************************************************/
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/*
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* These routines allow you to access data from within X-Plane and sometimes
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* modify it.
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*
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*/
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/*
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* XPLMDataRef
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*
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* A data ref is an opaque handle to data provided by the simulator or another
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* plugin. It uniquely identifies one variable (or array of variables) over
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* the lifetime of your plugin. You never hard code these values; you always
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* get them from XPLMFindDataRef.
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*
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*/
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typedef void * XPLMDataRef;
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/*
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* XPLMDataTypeID
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*
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* This is an enumeration that defines the type of the data behind a data
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* reference. This allows you to sanity check that the data type matches what
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* you expect. But for the most part, you will know the type of data you are
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* expecting from the online documentation.
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*
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* Data types each take a bit field; it is legal to have a single dataref be
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* more than one type of data. Whe this happens, you can pick any matching
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* get/set API.
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*
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*/
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enum {
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/* Data of a type the current XPLM doesn't do. */
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xplmType_Unknown = 0,
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/* A single 4-byte integer, native endian. */
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xplmType_Int = 1,
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/* A single 4-byte float, native endian. */
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xplmType_Float = 2,
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/* A single 8-byte double, native endian. */
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xplmType_Double = 4,
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/* An array of 4-byte floats, native endian. */
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xplmType_FloatArray = 8,
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/* An array of 4-byte integers, native endian. */
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xplmType_IntArray = 16,
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/* A variable block of data. */
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xplmType_Data = 32,
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};
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typedef int XPLMDataTypeID;
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/*
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* XPLMFindDataRef
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*
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* Given a c-style string that names the data ref, this routine looks up the
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* actual opaque XPLMDataRef that you use to read and write the data. The
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* string names for datarefs are published on the X-Plane SDK web site.
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*
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* This function returns NULL if the data ref cannot be found.
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*
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* NOTE: this function is relatively expensive; save the XPLMDataRef this
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* function returns for future use. Do not look up your data ref by string
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* every time you need to read or write it.
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*
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*/
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XPLM_API XPLMDataRef XPLMFindDataRef(
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const char * inDataRefName);
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/*
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* XPLMCanWriteDataRef
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*
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* Given a data ref, this routine returns true if you can successfully set the
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* data, false otherwise. Some datarefs are read-only.
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*
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* NOTE: even if a dataref is marked writable, it may not act writable. This
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* can happen for datarefs that X-Plane writes to on every frame of
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* simulation. In some cases, the dataref is writable but you have to set a
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* separate "override" dataref to 1 to stop X-Plane from writing it.
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*
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*/
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XPLM_API int XPLMCanWriteDataRef(
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XPLMDataRef inDataRef);
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/*
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* XPLMIsDataRefGood
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*
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* This function returns true if the passed in handle is a valid dataref that
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* is not orphaned.
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*
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* Note: there is normally no need to call this function; datarefs returned by
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* XPLMFindDataRef remain valid (but possibly orphaned) unless there is a
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* complete plugin reload (in which case your plugin is reloaded anyway).
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* Orphaned datarefs can be safely read and return 0. Therefore you never need
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* to call XPLMIsDataRefGood to 'check' the safety of a dataref.
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* (XPLMIsDatarefGood performs some slow checking of the handle validity, so
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* it has a perormance cost.)
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*
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*/
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XPLM_API int XPLMIsDataRefGood(
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XPLMDataRef inDataRef);
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/*
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* XPLMGetDataRefTypes
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*
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* This routine returns the types of the data ref for accessor use. If a data
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* ref is available in multiple data types, the bit-wise OR of these types
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* will be returned.
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*
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*/
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XPLM_API XPLMDataTypeID XPLMGetDataRefTypes(
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XPLMDataRef inDataRef);
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/***************************************************************************
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* DATA ACCESSORS
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***************************************************************************/
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/*
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* These routines read and write the data references. For each supported data
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* type there is a reader and a writer.
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*
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* If the data ref is orphaned or the plugin that provides it is disabled or
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* there is a type mismatch, the functions that read data will return 0 as a
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* default value or not modify the passed in memory. The plugins that write
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* data will not write under these circumstances or if the data ref is
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* read-only.
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*
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* NOTE: to keep the overhead of reading datarefs low, these routines do not
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* do full validation of a dataref; passing a junk value for a dataref can
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* result in crashing the sim. The get/set APIs do check for NULL.
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*
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* For array-style datarefs, you specify the number of items to read/write and
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* the offset into the array; the actual number of items read or written is
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* returned. This may be less to prevent an array-out-of-bounds error.
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*
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*/
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/*
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* XPLMGetDatai
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*
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* Read an integer data ref and return its value. The return value is the
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* dataref value or 0 if the dataref is NULL or the plugin is disabled.
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*
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*/
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XPLM_API int XPLMGetDatai(
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XPLMDataRef inDataRef);
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/*
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* XPLMSetDatai
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*
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* Write a new value to an integer data ref. This routine is a no-op if the
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* plugin publishing the dataref is disabled, the dataref is NULL, or the
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* dataref is not writable.
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*
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*/
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XPLM_API void XPLMSetDatai(
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XPLMDataRef inDataRef,
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int inValue);
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/*
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* XPLMGetDataf
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*
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* Read a single precision floating point dataref and return its value. The
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* return value is the dataref value or 0.0 if the dataref is NULL or the
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* plugin is disabled.
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*
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*/
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XPLM_API float XPLMGetDataf(
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XPLMDataRef inDataRef);
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/*
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* XPLMSetDataf
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*
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* Write a new value to a single precision floating point data ref. This
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* routine is a no-op if the plugin publishing the dataref is disabled, the
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* dataref is NULL, or the dataref is not writable.
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*
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*/
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XPLM_API void XPLMSetDataf(
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XPLMDataRef inDataRef,
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float inValue);
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/*
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* XPLMGetDatad
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*
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* Read a double precision floating point dataref and return its value. The
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* return value is the dataref value or 0.0 if the dataref is NULL or the
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* plugin is disabled.
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*
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*/
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XPLM_API double XPLMGetDatad(
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XPLMDataRef inDataRef);
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/*
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* XPLMSetDatad
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*
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* Write a new value to a double precision floating point data ref. This
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* routine is a no-op if the plugin publishing the dataref is disabled, the
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* dataref is NULL, or the dataref is not writable.
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*
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*/
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XPLM_API void XPLMSetDatad(
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XPLMDataRef inDataRef,
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double inValue);
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/*
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* XPLMGetDatavi
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*
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* Read a part of an integer array dataref. If you pass NULL for outValues,
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* the routine will return the size of the array, ignoring inOffset and inMax.
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*
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* If outValues is not NULL, then up to inMax values are copied from the
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* dataref into outValues, starting at inOffset in the dataref. If inMax +
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* inOffset is larger than the size of the dataref, less than inMax values
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* will be copied. The number of values copied is returned.
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*
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* Note: the semantics of array datarefs are entirely implemented by the
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* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
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* above description is how these datarefs are intended to work, but a rogue
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* plugin may have different behavior.
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*
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*/
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XPLM_API int XPLMGetDatavi(
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XPLMDataRef inDataRef,
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int * outValues, /* Can be NULL */
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int inOffset,
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int inMax);
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/*
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* XPLMSetDatavi
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*
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* Write part or all of an integer array dataref. The values passed by
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* inValues are written into the dataref starting at inOffset. Up to inCount
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* values are written; however if the values would write "off the end" of the
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* dataref array, then fewer values are written.
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*
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* Note: the semantics of array datarefs are entirely implemented by the
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* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
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* above description is how these datarefs are intended to work, but a rogue
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* plugin may have different behavior.
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*
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*/
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XPLM_API void XPLMSetDatavi(
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XPLMDataRef inDataRef,
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int * inValues,
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int inoffset,
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int inCount);
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/*
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* XPLMGetDatavf
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*
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* Read a part of a single precision floating point array dataref. If you pass
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* NULL for outVaules, the routine will return the size of the array, ignoring
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* inOffset and inMax.
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*
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* If outValues is not NULL, then up to inMax values are copied from the
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* dataref into outValues, starting at inOffset in the dataref. If inMax +
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* inOffset is larger than the size of the dataref, less than inMax values
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* will be copied. The number of values copied is returned.
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*
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* Note: the semantics of array datarefs are entirely implemented by the
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* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
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* above description is how these datarefs are intended to work, but a rogue
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* plugin may have different behavior.
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*
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*/
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XPLM_API int XPLMGetDatavf(
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XPLMDataRef inDataRef,
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float * outValues, /* Can be NULL */
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int inOffset,
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int inMax);
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/*
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* XPLMSetDatavf
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*
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* Write part or all of a single precision floating point array dataref. The
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* values passed by inValues are written into the dataref starting at
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* inOffset. Up to inCount values are written; however if the values would
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* write "off the end" of the dataref array, then fewer values are written.
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*
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* Note: the semantics of array datarefs are entirely implemented by the
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* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
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* above description is how these datarefs are intended to work, but a rogue
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* plugin may have different behavior.
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*
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*/
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XPLM_API void XPLMSetDatavf(
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XPLMDataRef inDataRef,
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float * inValues,
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int inoffset,
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int inCount);
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/*
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* XPLMGetDatab
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*
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* Read a part of a byte array dataref. If you pass NULL for outVaules, the
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* routine will return the size of the array, ignoring inOffset and inMax.
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*
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* If outValues is not NULL, then up to inMax values are copied from the
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* dataref into outValues, starting at inOffset in the dataref. If inMax +
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* inOffset is larger than the size of the dataref, less than inMax values
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* will be copied. The number of values copied is returned.
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*
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* Note: the semantics of array datarefs are entirely implemented by the
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* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
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* above description is how these datarefs are intended to work, but a rogue
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* plugin may have different behavior.
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*
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*/
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XPLM_API int XPLMGetDatab(
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XPLMDataRef inDataRef,
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void * outValue, /* Can be NULL */
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int inOffset,
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int inMaxBytes);
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/*
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* XPLMSetDatab
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*
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* Write part or all of a byte array dataref. The values passed by inValues
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* are written into the dataref starting at inOffset. Up to inCount values are
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* written; however if the values would write "off the end" of the dataref
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* array, then fewer values are written.
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*
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* Note: the semantics of array datarefs are entirely implemented by the
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* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
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* above description is how these datarefs are intended to work, but a rogue
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* plugin may have different behavior.
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*
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*/
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XPLM_API void XPLMSetDatab(
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XPLMDataRef inDataRef,
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void * inValue,
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int inOffset,
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int inLength);
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/***************************************************************************
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* PUBLISHING YOUR PLUGIN'S DATA
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***************************************************************************/
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/*
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* These functions allow you to create data references that other plug-ins and
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* X-Plane can access via the above data access APIs. Data references
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* published by other plugins operate the same as ones published by X-Plane in
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* all manners except that your data reference will not be available to other
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* plugins if/when your plugin is disabled.
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*
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* You share data by registering data provider callback functions. When a
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* plug-in requests your data, these callbacks are then called. You provide
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* one callback to return the value when a plugin 'reads' it and another to
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* change the value when a plugin 'writes' it.
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*
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* Important: you must pick a prefix for your datarefs other than "sim/" -
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* this prefix is reserved for X-Plane. The X-Plane SDK website contains a
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* registry where authors can select a unique first word for dataref names, to
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* prevent dataref collisions between plugins.
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*
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*/
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/*
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* XPLMGetDatai_f
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*
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* Data provider function pointers.
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*
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* These define the function pointers you provide to get or set data. Note
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* that you are passed a generic pointer for each one. This is the same
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* pointer you pass in your register routine; you can use it to locate plugin
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* variables, etc.
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*
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* The semantics of your callbacks are the same as the dataref accessor above
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* - basically routines like XPLMGetDatai are just pass-throughs from a caller
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* to your plugin. Be particularly mindful in implementing array dataref
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* read-write accessors; you are responsible for avoiding overruns, supporting
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* offset read/writes, and handling a read with a NULL buffer.
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*
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*/
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typedef int (* XPLMGetDatai_f)(
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void * inRefcon);
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/*
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* XPLMSetDatai_f
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*
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*/
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typedef void (* XPLMSetDatai_f)(
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void * inRefcon,
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int inValue);
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/*
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* XPLMGetDataf_f
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*
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*/
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typedef float (* XPLMGetDataf_f)(
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void * inRefcon);
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/*
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* XPLMSetDataf_f
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*
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*/
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typedef void (* XPLMSetDataf_f)(
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void * inRefcon,
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float inValue);
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/*
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* XPLMGetDatad_f
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*
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*/
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typedef double (* XPLMGetDatad_f)(
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void * inRefcon);
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/*
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* XPLMSetDatad_f
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*
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*/
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typedef void (* XPLMSetDatad_f)(
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void * inRefcon,
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double inValue);
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/*
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* XPLMGetDatavi_f
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*
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*/
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typedef int (* XPLMGetDatavi_f)(
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void * inRefcon,
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int * outValues, /* Can be NULL */
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int inOffset,
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int inMax);
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/*
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* XPLMSetDatavi_f
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*
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*/
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typedef void (* XPLMSetDatavi_f)(
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void * inRefcon,
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int * inValues,
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int inOffset,
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int inCount);
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/*
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* XPLMGetDatavf_f
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*
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*/
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typedef int (* XPLMGetDatavf_f)(
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void * inRefcon,
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float * outValues, /* Can be NULL */
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int inOffset,
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int inMax);
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/*
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* XPLMSetDatavf_f
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*
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*/
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typedef void (* XPLMSetDatavf_f)(
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void * inRefcon,
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float * inValues,
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int inOffset,
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int inCount);
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/*
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* XPLMGetDatab_f
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*
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*/
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typedef int (* XPLMGetDatab_f)(
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void * inRefcon,
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void * outValue, /* Can be NULL */
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int inOffset,
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int inMaxLength);
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/*
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* XPLMSetDatab_f
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*
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*/
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typedef void (* XPLMSetDatab_f)(
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void * inRefcon,
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void * inValue,
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int inOffset,
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int inLength);
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/*
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* XPLMRegisterDataAccessor
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*
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* This routine creates a new item of data that can be read and written. Pass
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* in the data's full name for searching, the type(s) of the data for
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* accessing, and whether the data can be written to. For each data type you
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* support, pass in a read accessor function and a write accessor function if
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* necessary. Pass NULL for data types you do not support or write accessors
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* if you are read-only.
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*
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* You are returned a data ref for the new item of data created. You can use
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* this data ref to unregister your data later or read or write from it.
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*
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*/
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XPLM_API XPLMDataRef XPLMRegisterDataAccessor(
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const char * inDataName,
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XPLMDataTypeID inDataType,
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int inIsWritable,
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XPLMGetDatai_f inReadInt,
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XPLMSetDatai_f inWriteInt,
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XPLMGetDataf_f inReadFloat,
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XPLMSetDataf_f inWriteFloat,
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XPLMGetDatad_f inReadDouble,
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XPLMSetDatad_f inWriteDouble,
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XPLMGetDatavi_f inReadIntArray,
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XPLMSetDatavi_f inWriteIntArray,
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XPLMGetDatavf_f inReadFloatArray,
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XPLMSetDatavf_f inWriteFloatArray,
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XPLMGetDatab_f inReadData,
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XPLMSetDatab_f inWriteData,
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void * inReadRefcon,
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void * inWriteRefcon);
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/*
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* XPLMUnregisterDataAccessor
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*
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* Use this routine to unregister any data accessors you may have registered.
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* You unregister a data ref by the XPLMDataRef you get back from
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* registration. Once you unregister a data ref, your function pointer will
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* not be called anymore.
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*
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*/
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|
XPLM_API void XPLMUnregisterDataAccessor(
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|
XPLMDataRef inDataRef);
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|
|
|
/***************************************************************************
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|
* SHARING DATA BETWEEN MULTIPLE PLUGINS
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|
***************************************************************************/
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|
/*
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|
* The data reference registration APIs from the previous section allow a
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* plugin to publish data in a one-owner manner; the plugin that publishes the
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* data reference owns the real memory that the data ref uses. This is
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|
* satisfactory for most cases, but there are also cases where plugnis need to
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* share actual data.
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|
*
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|
* With a shared data reference, no one plugin owns the actual memory for the
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|
* data reference; the plugin SDK allocates that for you. When the first
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|
* plugin asks to 'share' the data, the memory is allocated. When the data is
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|
* changed, every plugin that is sharing the data is notified.
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|
*
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|
* Shared data references differ from the 'owned' data references from the
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|
* previous section in a few ways:
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|
*
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|
* * With shared data references, any plugin can create the data reference;
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|
* with owned plugins one plugin must create the data reference and others
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|
* subscribe. (This can be a problem if you don't know which set of plugins
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|
* will be present).
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|
*
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|
* * With shared data references, every plugin that is sharing the data is
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|
* notified when the data is changed. With owned data references, only the
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|
* one owner is notified when the data is changed.
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|
*
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|
* * With shared data references, you cannot access the physical memory of the
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|
* data reference; you must use the XPLMGet... and XPLMSet... APIs. With an
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|
* owned data reference, the one owning data reference can manipulate the
|
|
* data reference's memory in any way it sees fit.
|
|
*
|
|
* Shared data references solve two problems: if you need to have a data
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|
* reference used by several plugins but do not know which plugins will be
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|
* installed, or if all plugins sharing data need to be notified when that
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|
* data is changed, use shared data references.
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|
*
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|
*/
|
|
|
|
|
|
/*
|
|
* XPLMDataChanged_f
|
|
*
|
|
* An XPLMDataChanged_f is a callback that the XPLM calls whenever any other
|
|
* plug-in modifies shared data. A refcon you provide is passed back to help
|
|
* identify which data is being changed. In response, you may want to call one
|
|
* of the XPLMGetDataxxx routines to find the new value of the data.
|
|
*
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|
*/
|
|
typedef void (* XPLMDataChanged_f)(
|
|
void * inRefcon);
|
|
|
|
/*
|
|
* XPLMShareData
|
|
*
|
|
* This routine connects a plug-in to shared data, creating the shared data if
|
|
* necessary. inDataName is a standard path for the data ref, and inDataType
|
|
* specifies the type. This function will create the data if it does not
|
|
* exist. If the data already exists but the type does not match, an error is
|
|
* returned, so it is important that plug-in authors collaborate to establish
|
|
* public standards for shared data.
|
|
*
|
|
* If a notificationFunc is passed in and is not NULL, that notification
|
|
* function will be called whenever the data is modified. The notification
|
|
* refcon will be passed to it. This allows your plug-in to know which shared
|
|
* data was changed if multiple shared data are handled by one callback, or if
|
|
* the plug-in does not use global variables.
|
|
*
|
|
* A one is returned for successfully creating or finding the shared data; a
|
|
* zero if the data already exists but is of the wrong type.
|
|
*
|
|
*/
|
|
XPLM_API int XPLMShareData(
|
|
const char * inDataName,
|
|
XPLMDataTypeID inDataType,
|
|
XPLMDataChanged_f inNotificationFunc,
|
|
void * inNotificationRefcon);
|
|
|
|
/*
|
|
* XPLMUnshareData
|
|
*
|
|
* This routine removes your notification function for shared data. Call it
|
|
* when done with the data to stop receiving change notifications. Arguments
|
|
* must match XPLMShareData. The actual memory will not necessarily be freed,
|
|
* since other plug-ins could be using it.
|
|
*
|
|
*/
|
|
XPLM_API int XPLMUnshareData(
|
|
const char * inDataName,
|
|
XPLMDataTypeID inDataType,
|
|
XPLMDataChanged_f inNotificationFunc,
|
|
void * inNotificationRefcon);
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif
|