c functions can't return C++ classes (at least not in MSVC)

sim/src/core/opSimulation/modules/Spawners/PreRunCommon/SpawnerPreRunCommonExport.cpp

@@ -20,14 +20,14 @@ extern "C" SPAWNPOINT_SHARED_EXPORT const std::string &OpenPASS_GetVersion()
     return Version;
 }
 
-extern "C" SPAWNPOINT_SHARED_EXPORT std::unique_ptr<SpawnPointInterface> OpenPASS_CreateInstance(const SpawnPointDependencies* dependencies,
+extern "C" SPAWNPOINT_SHARED_EXPORT SpawnPointInterface* OpenPASS_CreateInstance(const SpawnPointDependencies* dependencies,
                                                                                                  const CallbackInterface* callbacks)
 {
     Callbacks = callbacks;
 
     try
     {
-        return std::make_unique<SpawnerPreRunCommon>(dependencies,
+        return new SpawnerPreRunCommon(dependencies,
                                                         callbacks);
     }
     catch(const std::runtime_error &ex)
@@ -50,11 +50,11 @@ extern "C" SPAWNPOINT_SHARED_EXPORT std::unique_ptr<SpawnPointInterface> OpenPAS
     }
 }
 
-extern "C" SPAWNPOINT_SHARED_EXPORT SpawnPointInterface::Agents OpenPASS_Trigger(SpawnPointInterface *implementation, int time)
+extern "C" SPAWNPOINT_SHARED_EXPORT void OpenPASS_Trigger(SpawnPointInterface *implementation, int time, SpawnPointInterface::Agents &agents)
 {
     try
     {
-        return implementation->Trigger(time);
+        agents = implementation->Trigger(time);
     }
     catch(const std::runtime_error &ex)
     {
@@ -63,7 +63,7 @@ extern "C" SPAWNPOINT_SHARED_EXPORT SpawnPointInterface::Agents OpenPASS_Trigger
             Callbacks->Log(CbkLogLevel::Error, __FILE__, __LINE__, ex.what());
         }
 
-        return {};
+        return;
     }
     catch(...)
     {
@@ -71,6 +71,6 @@ extern "C" SPAWNPOINT_SHARED_EXPORT SpawnPointInterface::Agents OpenPASS_Trigger
         {
             Callbacks->Log(CbkLogLevel::Error, __FILE__, __LINE__, "unexpected exception");
         }
-        return {};
+        return;
     }
 }

sim/src/core/opSimulation/modules/Spawners/RuntimeCommon/SpawnerRuntimeCommonExport.cpp

@@ -24,14 +24,14 @@ extern "C" SPAWNPOINT_SHARED_EXPORT const std::string &OpenPASS_GetVersion()
     return Version;
 }
 
-extern "C" SPAWNPOINT_SHARED_EXPORT std::unique_ptr<SpawnPointInterface> OpenPASS_CreateInstance(const SpawnPointDependencies* dependencies,
+extern "C" SPAWNPOINT_SHARED_EXPORT SpawnPointInterface* OpenPASS_CreateInstance(const SpawnPointDependencies* dependencies,
                                                                                                  const CallbackInterface* callbacks)
 {
     Callbacks = callbacks;
 
     try
     {
-        return std::make_unique<SpawnerRuntimeCommon>(dependencies,
+        return  new SpawnerRuntimeCommon(dependencies,
                                                          callbacks);
     }
     catch(const std::runtime_error &ex)
@@ -54,7 +54,7 @@ extern "C" SPAWNPOINT_SHARED_EXPORT std::unique_ptr<SpawnPointInterface> OpenPAS
     }
 }
 
-extern "C" SPAWNPOINT_SHARED_EXPORT SpawnPointInterface::Agents OpenPASS_Trigger(SpawnPointInterface* implementation, int time)
+extern "C" SPAWNPOINT_SHARED_EXPORT void OpenPASS_Trigger(SpawnPointInterface *implementation, int time, SpawnPointInterface::Agents &agents)
 {
-    return implementation->Trigger(time);
+    agents = implementation->Trigger(time);
 }

sim/src/core/opSimulation/modules/Spawners/Scenario/SpawnerScenarioExport.cpp

@@ -20,14 +20,14 @@ extern "C" SPAWNPOINT_SHARED_EXPORT const std::string &OpenPASS_GetVersion()
     return Version;
 }
 
-extern "C" SPAWNPOINT_SHARED_EXPORT std::unique_ptr<SpawnPointInterface> OpenPASS_CreateInstance(const SpawnPointDependencies* dependencies,
+extern "C" SPAWNPOINT_SHARED_EXPORT SpawnPointInterface* OpenPASS_CreateInstance(const SpawnPointDependencies* dependencies,
                                                                                                  const CallbackInterface* callbacks)
 {
     Callbacks = callbacks;
 
     try
     {
-        return std::make_unique<SpawnerScenario>(dependencies,
+        return new SpawnerScenario(dependencies,
                                                     callbacks);
     }
     catch(const std::runtime_error &ex)
@@ -50,7 +50,7 @@ extern "C" SPAWNPOINT_SHARED_EXPORT std::unique_ptr<SpawnPointInterface> OpenPAS
     }
 }
 
-extern "C" SPAWNPOINT_SHARED_EXPORT SpawnPointInterface::Agents OpenPASS_Trigger(SpawnPointInterface *implementation, int time)
+extern "C" SPAWNPOINT_SHARED_EXPORT void OpenPASS_Trigger(SpawnPointInterface *implementation, int time, SpawnPointInterface::Agents &agents)
 {
-    return implementation->Trigger(time);
+    agents = implementation->Trigger(time);
 }