diff --git a/include/JSystem/J3DGraphBase/J3DShape.h b/include/JSystem/J3DGraphBase/J3DShape.h
index c96709d69..266636a8f 100644
--- a/include/JSystem/J3DGraphBase/J3DShape.h
+++ b/include/JSystem/J3DGraphBase/J3DShape.h
@@ -55,7 +55,7 @@ public:
 
 class J3DMaterial;
 class J3DVertexData;
-class J3DDrawMtxData;
+struct J3DDrawMtxData;
 
 enum J3DShpFlag {
     J3DShpFlag_Hide = 0x0001,
diff --git a/include/JSystem/J3DGraphBase/J3DTevs.h b/include/JSystem/J3DGraphBase/J3DTevs.h
index 10f13e343..d3d75b267 100644
--- a/include/JSystem/J3DGraphBase/J3DTevs.h
+++ b/include/JSystem/J3DGraphBase/J3DTevs.h
@@ -204,7 +204,7 @@ struct J3DNBTScale : public J3DNBTScaleInfo {
     Vec* getScale() { return &mScale; }
 };
 
-class J3DTexCoord;
+struct J3DTexCoord;
 void loadTexCoordGens(u32, J3DTexCoord*);
 void loadNBTScale(J3DNBTScale& param_0);
 
diff --git a/include/JSystem/J3DGraphLoader/J3DAnmLoader.h b/include/JSystem/J3DGraphLoader/J3DAnmLoader.h
index a97bf9953..5199d4d90 100644
--- a/include/JSystem/J3DGraphLoader/J3DAnmLoader.h
+++ b/include/JSystem/J3DGraphLoader/J3DAnmLoader.h
@@ -7,29 +7,29 @@ enum J3DAnmLoaderDataBaseFlag { J3DLOADER_UNK_FLAG0 };
 
 class J3DAnmBase;
 class J3DAnmClusterFull;
-class J3DAnmClusterFullData;
+struct J3DAnmClusterFullData;
 class J3DAnmClusterKey;
-class J3DAnmClusterKeyData;
+struct J3DAnmClusterKeyData;
 class J3DAnmColorFull;
-class J3DAnmColorFullData;
+struct J3DAnmColorFullData;
 class J3DAnmColorKey;
-class J3DAnmColorKeyData;
+struct J3DAnmColorKeyData;
 class J3DAnmTevRegKey;
-class J3DAnmTevRegKeyData;
+struct J3DAnmTevRegKeyData;
 class J3DAnmTexPattern;
-class J3DAnmTexPatternFullData;
+struct J3DAnmTexPatternFullData;
 class J3DAnmTextureSRTKey;
-class J3DAnmTextureSRTKeyData;
+struct J3DAnmTextureSRTKeyData;
 class J3DAnmTransformFull;
-class J3DAnmTransformFullData;
+struct J3DAnmTransformFullData;
 class J3DAnmTransformKey;
-class J3DAnmTransformKeyData;
+struct J3DAnmTransformKeyData;
 class J3DAnmVisibilityFull;
-class J3DAnmVisibilityFullData;
+struct J3DAnmVisibilityFullData;
 class J3DAnmVtxColorFull;
-class J3DAnmVtxColorFullData;
+struct J3DAnmVtxColorFullData;
 class J3DAnmVtxColorKey;
-class J3DAnmVtxColorKeyData;
+struct J3DAnmVtxColorKeyData;
 
 struct J3DAnmLoaderDataBase {
     static J3DAnmBase* load(const void*);
diff --git a/include/JSystem/J3DGraphLoader/J3DMaterialFactory.h b/include/JSystem/J3DGraphLoader/J3DMaterialFactory.h
index 8b6c52c67..d97cb0037 100644
--- a/include/JSystem/J3DGraphLoader/J3DMaterialFactory.h
+++ b/include/JSystem/J3DGraphLoader/J3DMaterialFactory.h
@@ -11,7 +11,7 @@ struct J3DMaterialDLBlock;
 struct J3DMaterialInitData;
 struct J3DIndInitData;
 struct J3DColorChanInfo;
-struct J3DLightInfo;
+class J3DLightInfo;
 struct J3DTexCoordInfo;
 struct J3DTexCoord2Info;
 struct J3DTexMtxInfo;
@@ -24,13 +24,13 @@ struct J3DAlphaCompInfo;
 struct J3DBlendInfo;
 struct J3DZModeInfo;
 struct J3DNBTScaleInfo;
-struct J3DCurrentMtxInfo;
+class J3DCurrentMtxInfo;
 
 struct J3DColorChan;
 struct J3DGXColor;
 struct J3DGXColorS10;
 struct J3DTexCoord;
-struct J3DTexMtx;
+class J3DTexMtx;
 struct J3DTevOrder;
 struct J3DTevStage;
 struct J3DTevSwapMode;
diff --git a/include/JSystem/J3DGraphLoader/J3DMaterialFactory_v21.h b/include/JSystem/J3DGraphLoader/J3DMaterialFactory_v21.h
index e1113eca5..d41547913 100644
--- a/include/JSystem/J3DGraphLoader/J3DMaterialFactory_v21.h
+++ b/include/JSystem/J3DGraphLoader/J3DMaterialFactory_v21.h
@@ -7,24 +7,24 @@
 
 class J3DMaterial;
 struct J3DMaterialBlock_v21;
-class J3DMaterialInitData_v21;
-class J3DIndInitData;
-class J3DColorChanInfo;
+struct J3DMaterialInitData_v21;
+struct J3DIndInitData;
+struct J3DColorChanInfo;
 class J3DLightInfo;
-class J3DTexCoordInfo;
-class J3DTexCoord2Info;
-class J3DTexMtxInfo;
-class J3DTevOrderInfo;
-class J3DTevStageInfo;
-class J3DTevSwapModeInfo;
-class J3DTevSwapModeTableInfo;
-class J3DFogInfo;
-class J3DAlphaCompInfo;
-class J3DBlendInfo;
-class J3DZModeInfo;
-class J3DNBTScaleInfo;
-class J3DDisplayListInit;
-class J3DPatchingInfo;
+struct J3DTexCoordInfo;
+struct J3DTexCoord2Info;
+struct J3DTexMtxInfo;
+struct J3DTevOrderInfo;
+struct J3DTevStageInfo;
+struct J3DTevSwapModeInfo;
+struct J3DTevSwapModeTableInfo;
+struct J3DFogInfo;
+struct J3DAlphaCompInfo;
+struct J3DBlendInfo;
+struct J3DZModeInfo;
+struct J3DNBTScaleInfo;
+struct J3DDisplayListInit;
+struct J3DPatchingInfo;
 class J3DCurrentMtxInfo;
 
 struct J3DMaterialInitData_v21 {
diff --git a/include/JSystem/JAudio/JAIAnimation.h b/include/JSystem/JAudio/JAIAnimation.h
index bed199d7c..9df256417 100644
--- a/include/JSystem/JAudio/JAIAnimation.h
+++ b/include/JSystem/JAudio/JAIAnimation.h
@@ -3,7 +3,7 @@
 
 #include "dolphin/types.h"
 
-class Vec;
+struct Vec;
 class JAISound;
 class JAIBasic;
 namespace JAInter {
diff --git a/include/JSystem/JAudio/JASDrumSet.h b/include/JSystem/JAudio/JASDrumSet.h
index f758d22ea..fd3dee3f1 100644
--- a/include/JSystem/JAudio/JASDrumSet.h
+++ b/include/JSystem/JAudio/JASDrumSet.h
@@ -5,7 +5,7 @@
 
 namespace JASystem {
     class TInstEffect;
-    class TInstParam;
+    struct TInstParam;
 
     class TDrumSet : public TInst {
     public:
diff --git a/include/JSystem/JAudio/osdsp.h b/include/JSystem/JAudio/osdsp.h
index 7cc4d6a1c..8e9e6e192 100644
--- a/include/JSystem/JAudio/osdsp.h
+++ b/include/JSystem/JAudio/osdsp.h
@@ -3,6 +3,6 @@
 
 #include "dolphin/dsp.h"
 
-void DSPAddPriorTask(STRUCT_DSP_TASK*);
+void DSPAddPriorTask(DSPTaskInfo*);
 
 #endif /* OSDSP_H */
diff --git a/include/JSystem/JAudio/osdsp_task.h b/include/JSystem/JAudio/osdsp_task.h
index 0000efd03..0a8db375e 100644
--- a/include/JSystem/JAudio/osdsp_task.h
+++ b/include/JSystem/JAudio/osdsp_task.h
@@ -8,7 +8,11 @@ typedef struct OSContext OSContext;
 
 extern DSPTaskInfo* DSP_prior_task;
 
+#ifdef __cplusplus
 extern "C" void __DSPHandler(int, OSContext*);
+#else
+void __DSPHandler(int, OSContext*);
+#endif
 void DsyncFrame2(u32, u32, u32);
 void Dsp_Update_Request();
 BOOL Dsp_Running_Check();
diff --git a/include/JSystem/JGadget/linklist.h b/include/JSystem/JGadget/linklist.h
index 2b60ce032..9ad3148d1 100644
--- a/include/JSystem/JGadget/linklist.h
+++ b/include/JSystem/JGadget/linklist.h
@@ -184,7 +184,7 @@ struct TLinkList_factory : public TLinkList<T, I> {
     virtual T* Do_create() = 0;
     virtual void Do_destroy(T*) = 0;
     void Erase_destroy(T* elem) {
-        Erase(elem);
+        this->Erase(elem);
         Do_destroy(elem);
     }
 };
diff --git a/include/JSystem/JMessage/processor.h b/include/JSystem/JMessage/processor.h
index f55597a5d..b63e80bef 100644
--- a/include/JSystem/JMessage/processor.h
+++ b/include/JSystem/JMessage/processor.h
@@ -7,7 +7,7 @@ namespace JMessage {
 
 struct TReference;
 struct TControl;
-struct TResource;
+class TResource;
 
 struct TProcessor {
 public:
@@ -80,7 +80,7 @@ public:
     static const char* process_select_(TProcessor*);
 
     void pushCurrent(const char*);
-    const char* popCurrent();
+    void popCurrent();
     void on_select_begin(OnSelectBeginCallBack, const void*, const char*, u32);
     void on_select_end();
     void on_select_separate();
diff --git a/include/JSystem/JParticle/JPAField.h b/include/JSystem/JParticle/JPAField.h
index f82dbadd7..ec36021e2 100644
--- a/include/JSystem/JParticle/JPAField.h
+++ b/include/JSystem/JParticle/JPAField.h
@@ -5,7 +5,7 @@
 #include "JSystem/JGeometry.h"
 
 class JPADataBlockLinkInfo;
-class JPAEmitterInfo;
+struct JPAEmitterInfo;
 class JPAFieldData;
 class JPABaseParticle;
 class JPABaseField;
diff --git a/include/JSystem/JStudio/JStudio/jstudio-control.h b/include/JSystem/JStudio/JStudio/jstudio-control.h
index 234e2e665..3fca92eee 100644
--- a/include/JSystem/JStudio/JStudio/jstudio-control.h
+++ b/include/JSystem/JStudio/JStudio/jstudio-control.h
@@ -8,7 +8,7 @@
 #include "dolphin/mtx/mtxvec.h"
 
 namespace JStudio {
-struct TObject;
+class TObject;
 struct TCreateObject {
     TCreateObject() {}
     virtual ~TCreateObject() = 0;
diff --git a/include/JSystem/JStudio/JStudio/stb.h b/include/JSystem/JStudio/JStudio/stb.h
index 5735c9282..03c68331f 100644
--- a/include/JSystem/JStudio/JStudio/stb.h
+++ b/include/JSystem/JStudio/JStudio/stb.h
@@ -7,7 +7,7 @@
 #include "global.h"
 
 namespace JStudio {
-struct TObject;
+class TObject;
 namespace stb {
 
 class TControl;
diff --git a/include/JSystem/JStudio/JStudio_JAudio/control.h b/include/JSystem/JStudio/JStudio_JAudio/control.h
index d87b83b7e..4e8010ab2 100644
--- a/include/JSystem/JStudio/JStudio_JAudio/control.h
+++ b/include/JSystem/JStudio/JStudio_JAudio/control.h
@@ -5,8 +5,8 @@
 #include "JSystem/JStudio/JStudio/jstudio-object.h"
 #include "JSystem/JStage/JSGSystem.h"
 
-struct JAIBasic;
-struct JAISound;
+class JAIBasic;
+class JAISound;
 namespace JStudio_JAudio {
 typedef JStudio::TObject* (*JStudioAudioCreateFunc)(const JStudio::stb::data::TParse_TBlock_object&, JAIBasic*);
 typedef void (JAISound::*TVVOSoundSetFunc)(f32, u32); // e.g. JAISound::setDirectVolume, JAISound::setDirectPitch
diff --git a/include/SSystem/SComponent/c_m2d.h b/include/SSystem/SComponent/c_m2d.h
index 8fca640d9..ade8e9d21 100644
--- a/include/SSystem/SComponent/c_m2d.h
+++ b/include/SSystem/SComponent/c_m2d.h
@@ -3,7 +3,7 @@
 
 #include "global.h"
 
-struct cM2dGCir;
+class cM2dGCir;
 
 void cM2d_CrossCirLin(cM2dGCir&, float, float, float, float, float*, float*);
 
diff --git a/include/d/actor/d_a_bk.h b/include/d/actor/d_a_bk.h
index 6b528d057..ab0cdaf0f 100644
--- a/include/d/actor/d_a_bk.h
+++ b/include/d/actor/d_a_bk.h
@@ -6,7 +6,7 @@
 #include "SSystem/SComponent/c_phase.h"
 #include "m_Do/m_Do_hostIO.h"
 
-class dPath;
+struct dPath;
 namespace daObj_Search { class Act_c; };
 struct br_s;
 
diff --git a/include/d/actor/d_a_wind_tag.h b/include/d/actor/d_a_wind_tag.h
index 6d3a04e0f..441e63593 100644
--- a/include/d/actor/d_a_wind_tag.h
+++ b/include/d/actor/d_a_wind_tag.h
@@ -8,7 +8,7 @@
 #include "m_Do/m_Do_ext.h"
 
 class JPABaseEmitter;
-class dPath;
+struct dPath;
 
 namespace daWindTag {
     static BOOL CheckCreateHeap(fopAc_ac_c*);
diff --git a/include/d/actor/d_a_ykgr.h b/include/d/actor/d_a_ykgr.h
index 8ee54cc71..7f1194170 100644
--- a/include/d/actor/d_a_ykgr.h
+++ b/include/d/actor/d_a_ykgr.h
@@ -3,7 +3,7 @@
 
 #include "f_op/f_op_actor.h"
 
-class dPath;
+struct dPath;
 class JPABaseEmitter;
 class JPABaseParticle;
 
diff --git a/include/d/d_2dnumber.h b/include/d/d_2dnumber.h
index 9e5c4e7bd..9e93d2e9d 100644
--- a/include/d/d_2dnumber.h
+++ b/include/d/d_2dnumber.h
@@ -5,7 +5,7 @@
 
 struct ResTIMG;
 class JUTFont;
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 
 class dDlst_2DNumber_c : public dDlst_base_c {
 public:
diff --git a/include/d/d_auction_screen.h b/include/d/d_auction_screen.h
index 638690ae5..bfa2c7e3c 100644
--- a/include/d/d_auction_screen.h
+++ b/include/d/d_auction_screen.h
@@ -3,7 +3,7 @@
 
 #include "dolphin/types.h"
 
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 class J2DPane;
 class JKRArchive;
 
diff --git a/include/d/d_camera.h b/include/d/d_camera.h
index d3e54ccf5..0f3713205 100644
--- a/include/d/d_camera.h
+++ b/include/d/d_camera.h
@@ -17,7 +17,7 @@ class camera_process_class;
 class dBgS_LinChk;
 class dBgS_CamGndChk;
 class d2DBSplinePath;
-class dStage_Event_dt_c;
+struct dStage_Event_dt_c;
 class fopAc_ac_c;
 
 struct dCamera__EventParam {
diff --git a/include/d/d_com_inf_game.h b/include/d/d_com_inf_game.h
index 91569f9df..636e71458 100644
--- a/include/d/d_com_inf_game.h
+++ b/include/d/d_com_inf_game.h
@@ -3544,7 +3544,7 @@ inline void dComIfGp_setFmapData(void * pData) { g_dComIfG_gameInfo.play.setFmap
  * === RESOURCE ===
  */
 
-class request_of_phase_process_class;
+struct request_of_phase_process_class;
 cPhs_State dComIfG_resLoad(request_of_phase_process_class* i_phase, char const* arc_name);
 int dComIfG_resDelete(request_of_phase_process_class* i_phase, char const* resName);
 
diff --git a/include/d/d_drawlist.h b/include/d/d_drawlist.h
index e0b177519..267ee99cb 100644
--- a/include/d/d_drawlist.h
+++ b/include/d/d_drawlist.h
@@ -9,7 +9,7 @@
 #include "SSystem/SComponent/c_rnd.h"
 #include "global.h"
 
-class ResTIMG;
+struct ResTIMG;
 class cM3dGPla;
 
 class dDlst_base_c {
@@ -427,7 +427,7 @@ public:
 
 struct view_port_class;
 struct view_class;
-struct camera_class;
+class camera_class;
 
 struct dDlst_alphaModelData_c {
 public:
diff --git a/include/d/d_event.h b/include/d/d_event.h
index 70a2355a1..4d7556e73 100644
--- a/include/d/d_event.h
+++ b/include/d/d_event.h
@@ -56,7 +56,7 @@ public:
     /* 0x15 */ u8 mEventInfoIdx;
 };  // Size = 0x18
 
-class dStage_Event_dt_c;
+struct dStage_Event_dt_c;
 
 enum dTalkXYButton_e {
     dTalkBtn_NONE_e = 0,
diff --git a/include/d/d_kankyo.h b/include/d/d_kankyo.h
index fbf354327..f7139dc8a 100644
--- a/include/d/d_kankyo.h
+++ b/include/d/d_kankyo.h
@@ -157,13 +157,13 @@ class dKankyo_cloud_Packet;
 class dKankyo_vrkumo_Packet;
 class dKankyo_wave_Packet;
 class dKankyo_poison_Packet;
-class WINDEFF_SET;
+struct WINDEFF_SET;
 class dKankyo_star_Packet;
-class stage_palet_info_class;
-class stage_pselect_info_class;
-class stage_envr_info_class;
-class stage_vrbox_info_class;
-class stage_plight_info_class;
+struct stage_palet_info_class;
+struct stage_pselect_info_class;
+struct stage_envr_info_class;
+struct stage_vrbox_info_class;
+struct stage_plight_info_class;
 struct dKyd_Schedule;
 
 class dScnKy_env_light_c {
diff --git a/include/d/d_kankyo_demo.h b/include/d/d_kankyo_demo.h
index 58b449e82..662099633 100644
--- a/include/d/d_kankyo_demo.h
+++ b/include/d/d_kankyo_demo.h
@@ -3,7 +3,7 @@
 
 #include "d/d_kankyo.h"
 
-struct cXyz;
+class cXyz;
 
 struct DEMO_PLIGHT {
     /* 0x00 */ int field_0x00;
diff --git a/include/d/d_kankyo_wether.h b/include/d/d_kankyo_wether.h
index 196b07490..81ddd4024 100644
--- a/include/d/d_kankyo_wether.h
+++ b/include/d/d_kankyo_wether.h
@@ -8,7 +8,7 @@
 
 class JUTTexture;
 class JPABaseEmitter;
-class WIND_INFLUENCE;
+struct WIND_INFLUENCE;
 
 class dKankyo_sun_Packet : public J3DPacket {
 public:
diff --git a/include/d/d_map.h b/include/d/d_map.h
index 21ca97126..6ee765ad2 100644
--- a/include/d/d_map.h
+++ b/include/d/d_map.h
@@ -8,7 +8,7 @@ struct ResTIMG;
 struct dmap_dmap_tlut_s;
 class fopAc_ac_c;
 struct map_dt_c;
-class stage_map_info_class;
+struct stage_map_info_class;
 
 class dMap_2DMtMapSpcl_tex_c {
 public:
diff --git a/include/d/d_menu_collect.h b/include/d/d_menu_collect.h
index 66a505eab..a556326b7 100644
--- a/include/d/d_menu_collect.h
+++ b/include/d/d_menu_collect.h
@@ -3,7 +3,7 @@
 
 #include "dolphin/types.h"
 
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 class JKRArchive;
 class JUTFont;
 
diff --git a/include/d/d_menu_dmap.h b/include/d/d_menu_dmap.h
index 3c8e28349..54d8679da 100644
--- a/include/d/d_menu_dmap.h
+++ b/include/d/d_menu_dmap.h
@@ -4,7 +4,7 @@
 #include "dolphin/types.h"
 
 class J2DPane;
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 class JKRArchive;
 class JUTFont;
 
diff --git a/include/d/d_menu_fmap.h b/include/d/d_menu_fmap.h
index cea276f39..b1acbbcf4 100644
--- a/include/d/d_menu_fmap.h
+++ b/include/d/d_menu_fmap.h
@@ -6,7 +6,7 @@
 
 class JUTFont;
 class J2DScreen;
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 class dMenu_FmapSv_c;
 struct cursorTable_t;
 struct aramCmapDatPat_t;
diff --git a/include/d/d_menu_fmap2.h b/include/d/d_menu_fmap2.h
index 1c0e4658e..96f6a0bca 100644
--- a/include/d/d_menu_fmap2.h
+++ b/include/d/d_menu_fmap2.h
@@ -3,9 +3,9 @@
 
 #include "dolphin/types.h"
 
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 class J2DScreen;
-class ResTIMG;
+struct ResTIMG;
 class aramCmapDat_c;
 class dMenu_FmapSv_c;
 
diff --git a/include/d/d_menu_item.h b/include/d/d_menu_item.h
index e44263f2a..2c4a028ea 100644
--- a/include/d/d_menu_item.h
+++ b/include/d/d_menu_item.h
@@ -3,7 +3,7 @@
 
 #include "dolphin/types.h"
 
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 class JKRArchive;
 class JUTFont;
 class J2DPane;
diff --git a/include/d/d_menu_option.h b/include/d/d_menu_option.h
index 353177b2b..c3529d8bf 100644
--- a/include/d/d_menu_option.h
+++ b/include/d/d_menu_option.h
@@ -7,7 +7,7 @@
 #include "f_op/f_op_msg_mng.h"
 #include "m_Do/m_Do_hostIO.h"
 
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 class JKRArchive;
 class JUTFont;
 
diff --git a/include/d/d_menu_save.h b/include/d/d_menu_save.h
index 2cc0edbc2..9d4733cb6 100644
--- a/include/d/d_menu_save.h
+++ b/include/d/d_menu_save.h
@@ -4,7 +4,7 @@
 #include "d/d_drawlist.h"
 #include "dolphin/types.h"
 
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 
 class dDlst_MenuSave_c : public dDlst_base_c {
 public:
diff --git a/include/d/d_meter.h b/include/d/d_meter.h
index 3cebe8609..f67692867 100644
--- a/include/d/d_meter.h
+++ b/include/d/d_meter.h
@@ -8,7 +8,7 @@
 class J2DPane;
 class JPABaseEmitter;
 class fopAc_ac_c;
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 class msg_class;
 class sub_meter_class;
 
diff --git a/include/d/d_minigame_starter.h b/include/d/d_minigame_starter.h
index 071910c3c..0dcf993b7 100644
--- a/include/d/d_minigame_starter.h
+++ b/include/d/d_minigame_starter.h
@@ -4,7 +4,7 @@
 #include "dolphin/types.h"
 
 class JKRArchive;
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 
 class dDlst_StarterScrnDraw_c {
 public:
diff --git a/include/d/d_minigame_terminater.h b/include/d/d_minigame_terminater.h
index 6dc38e5d8..bc3420ebd 100644
--- a/include/d/d_minigame_terminater.h
+++ b/include/d/d_minigame_terminater.h
@@ -5,7 +5,7 @@
 
 class JKRArchive;
 class J2DPane;
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 
 class dDlst_TerminaterScrnDraw_c {
 public:
diff --git a/include/d/d_operate_wind.h b/include/d/d_operate_wind.h
index 69169e2b9..94edb695b 100644
--- a/include/d/d_operate_wind.h
+++ b/include/d/d_operate_wind.h
@@ -7,7 +7,7 @@
 #include "m_Do/m_Do_hostIO.h"
 #include "JSystem/JUtility/TColor.h"
 
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 class JKRExpHeap;
 class J2DScreen;
 class STControl;
diff --git a/include/d/d_particle.h b/include/d/d_particle.h
index 4e47625bd..48246d3dc 100644
--- a/include/d/d_particle.h
+++ b/include/d/d_particle.h
@@ -20,7 +20,7 @@ class JKRHeap;
 class JPABaseEmitter;
 class JPAEmitterManager;
 class J3DModelData;
-struct csXyz;
+class csXyz;
 
 class dPa_simpleData_c {
 public:
diff --git a/include/d/d_picture_box.h b/include/d/d_picture_box.h
index 3d8a90205..5d8ac4490 100644
--- a/include/d/d_picture_box.h
+++ b/include/d/d_picture_box.h
@@ -4,8 +4,8 @@
 #include "dolphin/types.h"
 
 class JKRExpHeap;
-class fopMsgM_pane_class;
-class fopMsgM_pane_alpha_class;
+struct fopMsgM_pane_class;
+struct fopMsgM_pane_alpha_class;
 
 class sub_pb_class;
 
diff --git a/include/dolphin/os/OSAlarm.h b/include/dolphin/os/OSAlarm.h
index 658e988e6..9bdb4f2f1 100644
--- a/include/dolphin/os/OSAlarm.h
+++ b/include/dolphin/os/OSAlarm.h
@@ -13,7 +13,7 @@ typedef struct OSAlarmLink {
     /* 0x4 */ struct OSAlarm* next;
 } OSAlarmLink;
 
-typedef struct OSAlarm;
+typedef struct OSAlarm OSAlarm;
 typedef void (*OSAlarmHandler)(struct OSAlarm* alarm, OSContext* context);
 
 typedef struct OSAlarm {
diff --git a/src/JSystem/J2DGraph/J2DTextBox.cpp b/src/JSystem/J2DGraph/J2DTextBox.cpp
index 8cd798a82..6897ff650 100644
--- a/src/JSystem/J2DGraph/J2DTextBox.cpp
+++ b/src/JSystem/J2DGraph/J2DTextBox.cpp
@@ -9,7 +9,7 @@
 #include "JSystem/JUtility/JUTResource.h"
 #include "JSystem/J2DGraph/J2DPrint.h"
 #include "dolphin/gx/GXTransform.h"
-#include "__va_arg.h"
+#include "stdarg.h"
 
 /* 802D51D8-802D5268       .text __ct__10J2DTextBoxFPCcPCc */
 J2DTextBox::J2DTextBox(const char* font, const char* str) : mpFont(NULL), mStringPtr(NULL) {
diff --git a/src/JSystem/JAudio/dspproc.c b/src/JSystem/JAudio/dspproc.c
index ddddb8fdc..71f0d6d80 100644
--- a/src/JSystem/JAudio/dspproc.c
+++ b/src/JSystem/JAudio/dspproc.c
@@ -4,9 +4,10 @@
 //
 
 #include "JSystem/JAudio/dspproc.h"
-#include "JSystem/JAudio/JASDSPInterface.h"
 #include "JSystem/JAudio/dsptask.h"
 
+u16 DSP_CreateMap2(u32 param_1);
+
 /* 8028E600-8028E648       .text DSPReleaseHalt2__FUl */
 void DSPReleaseHalt2(u32 msg) {
     u32 msgs[2];
@@ -26,7 +27,7 @@ void DSPReleaseHalt() {
 static volatile BOOL flag;
 
 /* 8028E6A0-8028E6AC       .text setup_callback__FUs */
-void setup_callback(u16) {
+void setup_callback(u16 param_1) {
     flag = 0;
 }
 
@@ -40,7 +41,7 @@ void DsetupTable(u32 param_1, u32 param_2, u32 param_3, u32 param_4, u32 param_5
     table[4] = param_5;
     flag = 1;
     DSPSendCommands2(table,5,setup_callback);
-    while (true) {
+    while (TRUE) {
         if (flag == 0) {
             return;
         }
@@ -66,7 +67,7 @@ void DsyncFrame(u32 param_1, u32 param_2, u32 param_3) {
 static volatile BOOL d_waitflag;
 
 /* 8028E7E0-8028E7EC       .text dummy_callback__FUs */
-void dummy_callback(u16) {
+void dummy_callback(u16 param_1) {
     d_waitflag = 0;
 }
 
diff --git a/src/JSystem/JAudio/dsptask.c b/src/JSystem/JAudio/dsptask.c
index ef0b1849e..015e0a76d 100644
--- a/src/JSystem/JAudio/dsptask.c
+++ b/src/JSystem/JAudio/dsptask.c
@@ -10,7 +10,7 @@
 #include "global.h"
 
 /* 8028E860-8028E898       .text DspHandShake__FPv */
-void DspHandShake(void*) {
+void DspHandShake(void* param_1) {
     while (DSPCheckMailFromDSP() == 0) {}
     DSPReadMailFromDSP();
     DSPCheckMailFromDSP();
diff --git a/src/JSystem/JMessage/processor.cpp b/src/JSystem/JMessage/processor.cpp
index 036a2efad..5f30258af 100644
--- a/src/JSystem/JMessage/processor.cpp
+++ b/src/JSystem/JMessage/processor.cpp
@@ -54,7 +54,7 @@ void TProcessor::pushCurrent(const char* v) {
 }
 
 /* 8029EEA4-8029EEC8       .text popCurrent__Q28JMessage10TProcessorFv */
-const char* TProcessor::popCurrent() {
+void TProcessor::popCurrent() {
     setCurrent_(mStack.top());
     mStack.pop();
 }
diff --git a/src/JSystem/JStudio/JStudio/functionvalue.cpp b/src/JSystem/JStudio/JStudio/functionvalue.cpp
index 3ed957c92..ff75c00f8 100644
--- a/src/JSystem/JStudio/JStudio/functionvalue.cpp
+++ b/src/JSystem/JStudio/JStudio/functionvalue.cpp
@@ -8,7 +8,7 @@
 #include "JSystem/JGadget/linklist.h"
 #include "dolphin/types.h"
 #include "math.h"
-#include "arith.h"
+#include "stdlib.h"
 
 namespace JStudio {
 
diff --git a/src/d/actor/d_a_player_boomerang.inc b/src/d/actor/d_a_player_boomerang.inc
index 5ee1a5914..386f081ed 100644
--- a/src/d/actor/d_a_player_boomerang.inc
+++ b/src/d/actor/d_a_player_boomerang.inc
@@ -91,10 +91,10 @@ BOOL daPy_lk_c::checkNextActionBoomerangReady() {
 /* 8014984C-801498D8       .text checkNextActionBoomerangFly__9daPy_lk_cFv */
 BOOL daPy_lk_c::checkNextActionBoomerangFly() {
     if (checkBoomerangReadyAnime()) {
-        checkNextActionBoomerangReady();
+        return checkNextActionBoomerangReady();
     } else {
         if (itemTrigger() && mEquipItem == getReadyItem()) {
-            setActAnimeUpper(
+            return setActAnimeUpper(
                 LKANM_BCK_BOOMWAIT,
                 UPPER_MOVE2_e,
                 daPy_HIO_boom_c0::m.field_0x18,
@@ -112,9 +112,9 @@ BOOL daPy_lk_c::checkNextBoomerangMode() {
         seStartOnlyReverb(JA_SE_LK_ITEM_TAKEOUT);
     }
     if (mpAttention->Lockon()) {
-        procBoomerangMove_init();
+        return procBoomerangMove_init();
     } else {
-        procBoomerangSubject_init();
+        return procBoomerangSubject_init();
     }
 }
 
diff --git a/src/d/actor/d_a_player_bottle.inc b/src/d/actor/d_a_player_bottle.inc
index b325df916..3415d11fa 100644
--- a/src/d/actor/d_a_player_bottle.inc
+++ b/src/d/actor/d_a_player_bottle.inc
@@ -87,7 +87,7 @@ void daPy_lk_c::setBottleModel(u16 param_0) {
 fopAc_ac_c* daPy_lk_c::makeFairy(cXyz* param_0, u32 param_1) {
     onResetFlg0(daPyRFlg0_FAIRY_USE);
     resetCurse();
-    fopAcM_fastCreate(PROC_NPC_FA1, param_1, param_0, fopAcM_GetRoomNo(this), &shape_angle);
+    return (fopAc_ac_c*)fopAcM_fastCreate(PROC_NPC_FA1, param_1, param_0, fopAcM_GetRoomNo(this), &shape_angle);
 }
 
 /* 801521A0-80152300       .text procBottleDrink_init__9daPy_lk_cFUs */
diff --git a/src/d/actor/d_a_player_hook.inc b/src/d/actor/d_a_player_hook.inc
index ebca8d154..fb27d5c63 100644
--- a/src/d/actor/d_a_player_hook.inc
+++ b/src/d/actor/d_a_player_hook.inc
@@ -187,9 +187,9 @@ BOOL daPy_lk_c::checkNextHookshotMode() {
         seStartOnlyReverb(JA_SE_LK_ITEM_TAKEOUT);
     }
     if (mpAttention->Lockon()) {
-        procHookshotMove_init();
+        return procHookshotMove_init();
     } else {
-        procHookshotSubject_init();
+        return procHookshotSubject_init();
     }
 }
 
diff --git a/src/d/actor/d_a_player_rope.inc b/src/d/actor/d_a_player_rope.inc
index 671643e57..8d79689aa 100644
--- a/src/d/actor/d_a_player_rope.inc
+++ b/src/d/actor/d_a_player_rope.inc
@@ -50,7 +50,7 @@ f32 daPy_lk_c::checkRopeRoofHit(s16 param_0) {
 
     local_c.set(current.pos.x - 15.0f * cM_ssin(param_0), current.pos.y, current.pos.z - 15.0f * cM_scos(param_0));
     mRoofChk.SetPos(local_c);
-    dComIfG_Bgsp()->RoofChk(&mRoofChk);
+    return dComIfG_Bgsp()->RoofChk(&mRoofChk);
 }
 
 /* 80142E98-80142FC8       .text changeRopeSwingProc__9daPy_lk_cFv */
@@ -317,9 +317,9 @@ BOOL daPy_lk_c::checkNextRopeMode() {
         seStartOnlyReverb(JA_SE_LK_ITEM_TAKEOUT);
     }
     if (mpAttention->Lockon()) {
-        procRopeMove_init();
+        return procRopeMove_init();
     } else {
-        procRopeSubject_init();
+        return procRopeSubject_init();
     }
 }
 
diff --git a/src/d/d_camera.cpp b/src/d/d_camera.cpp
index 167d1afb2..60d6e8a72 100644
--- a/src/d/d_camera.cpp
+++ b/src/d/d_camera.cpp
@@ -2276,7 +2276,7 @@ void dCamera_c::checkGroundInfo() {
 
 /* 8016A0F0-8016A110       .text followCamera2__9dCamera_cFl */
 bool dCamera_c::followCamera2(s32 param_0) {
-    followCamera(param_0);
+    return followCamera(param_0);
 }
 
 /* 8016A110-8016C4F8       .text followCamera__9dCamera_cFl */
diff --git a/src/d/d_mesg.cpp b/src/d/d_mesg.cpp
index a92cf7016..61edbd796 100644
--- a/src/d/d_mesg.cpp
+++ b/src/d/d_mesg.cpp
@@ -624,7 +624,7 @@ bool dMesg_tSequenceProcessor::do_tag(u32 param_1, const void* param_2, u32 para
         }
         }
         break;
-    case 0x10000:
+    case 0x10000: {
         u16 r24 = param_1 & 0xFFFF;
         s8 tmp = dComIfGp_getReverb(dComIfGp_roomControl_getStayNo());
         if (r24 == 8) {
@@ -634,6 +634,7 @@ bool dMesg_tSequenceProcessor::do_tag(u32 param_1, const void* param_2, u32 para
         }
         r29 = true;
         break;
+    }
     case 0x20000:
         dComIfGp_setMesgCameraTagInfo(u16(param_1));
         r29 = true;
@@ -1552,7 +1553,8 @@ void dMesg_screenDataItem_c::createScreen() {
         J2DPane* pane = field_0x1b4.pane;
         f32 y = (field_0x1b4.mSize.y * 0.5f + pane->mScreenBounds.i.y - 240.0f) - 10.0f;
         f32 x = (field_0x1b4.mSize.x * 0.5f + pane->mScreenBounds.i.x - 320.0f) + 10.0f;
-        field_0x3e4 = dComIfGp_particle_set2Dfore(0x2e1, &cXyz(x, y, 0.0f));
+        cXyz pos(x, y, 0.0f);
+        field_0x3e4 = dComIfGp_particle_set2Dfore(0x2e1, &pos);
     }
 }
 
diff --git a/src/d/d_msg.cpp b/src/d/d_msg.cpp
index 1e6ef4a1b..7beeeabb7 100644
--- a/src/d/d_msg.cpp
+++ b/src/d/d_msg.cpp
@@ -7,7 +7,7 @@
 #include "dolphin/types.h"
 
 class J2DTextBox;
-class fopMsgM_pane_class;
+struct fopMsgM_pane_class;
 
 J2DPicture* button_icon[8];
 J2DPicture* button_kage[8];
diff --git a/src/f_op/f_op_msg_mng.cpp b/src/f_op/f_op_msg_mng.cpp
index b6b1b4291..fbfb16958 100644
--- a/src/f_op/f_op_msg_mng.cpp
+++ b/src/f_op/f_op_msg_mng.cpp
@@ -144,8 +144,7 @@ static struct {
     /* 0x3B */ {PRESIDENT_STATUE, "beast_12.bti"},
 };
 
-class mesg_header;
-class fopMsgM_pane_alpha_class;
+struct fopMsgM_pane_alpha_class;
 
 
 /* 8002ABB4-8002AC1C       .text drawSelf__9MyPictureFff */
@@ -647,6 +646,7 @@ char* fopMsgM_messageGet(char* dst, u32 msgNo) {
     }
 
     dst[numRead] = '\0';
+    return dst;
 }
 
 /* 8002BE04-8002C02C       .text fopMsgM_passwordGet__FPcUl */
diff --git a/src/m_Do/m_Do_MemCardRWmng.cpp b/src/m_Do/m_Do_MemCardRWmng.cpp
index 9a2ace43a..4555ae168 100644
--- a/src/m_Do/m_Do_MemCardRWmng.cpp
+++ b/src/m_Do/m_Do_MemCardRWmng.cpp
@@ -13,7 +13,7 @@
 #include "dolphin/os/OS.h"
 
 #include <string.h>
-#include <printf.h>
+#include <stdio.h>
 
 static u8 sTmpBuf[0x2000] ALIGN_DECL(32);
 static u8 sTmpBuf2[0x2000] ALIGN_DECL(32);