X-Plane flight loop callback demo

1_with_ppl.cpp

// complete plugin using PPL
#include <cstring>
#include <memory>

#include <XPLMPlugin.h>
#include <XPLMUtilities.h>

#include <processor.h>

class Foo : PPL::Processor {
  // callback function inherited from Processor
  virtual float callback(float, float, int) override {
    // do whatever this plugin's made to do
    if (tick)
    XPLMSpeakString("No luck catching them swans then");
  else
    XPLMSpeakString("It's just the one swan actually");
    tick = !tick;

    // call again after 10 seconds
    return 10;
  }
  bool tick;
};

// using unique_ptr and make_unique is an easy way to make sure everything gets
// set up nice and safely at a precise point during XPluginStart
static std::unique_ptr<Foo> foo;

PLUGIN_API int XPluginStart(char* outName, char* outSig, char* outDesc) {
  char name[] = "flcb";
  strcpy(outName, name);
  strcpy(outSig, name);
  strcpy(outDesc, name);

  foo = std::make_unique<Foo>();

  return 1;
}

PLUGIN_API void XPluginStop(void) {}
PLUGIN_API void XPluginDisable(void) {}
PLUGIN_API int XPluginEnable(void) {
  return 1;
}
PLUGIN_API void XPluginReceiveMessage(XPLMPluginID, long, void*) {}

2_sdk_only.cpp

// complete plugin using SDK directly
#include <cstring>

#include <XPLMPlugin.h>
#include <XPLMUtilities.h>
#include <XPLMProcessing.h>

// declare the values, datarefs, commands etc
static bool tick;

// callback functions need this signature
float callback(float, float, int, void*) {
  // do whatever this plugin's made to do
  if (tick)
    XPLMSpeakString("No luck catching them swans then");
  else
    XPLMSpeakString("It's just the one swan actually");
  tick = !tick;

  // call this function again after 10 seconds
  return 10;
}

PLUGIN_API int XPluginStart(char* outName, char* outSig, char* outDesc) {
  char name[] = "flcb";
  strcpy(outName, name);
  strcpy(outSig, name);
  strcpy(outDesc, name);

  XPLMRegisterFlightLoopCallback(callback, 10, nullptr);

  return 1;
}

PLUGIN_API void XPluginStop(void) {
  // if you forget this the UNIVERSE EXPLODES possibly
  XPLMUnregisterFlightLoopCallback(callback, nullptr);
}

PLUGIN_API void XPluginDisable(void) {}
PLUGIN_API int XPluginEnable(void) {
  return 1;
}
PLUGIN_API void XPluginReceiveMessage(XPLMPluginID, long, void*) {}