Added FCEU_UNUSED and FCEU_MAYBE_UNUSED macros to help silence certain unused variable and function warnings. Used FCEU_MAYBE_UNUSED to silence unused static function warnings (until it can be deemed that these functions will never be needed). Also, cleaned up a few other unused variable warnings.

src/boards/coolgirl.cpp

@@ -519,7 +519,7 @@ static DECLFW(COOLGIRL_Flash_Write) {
 			(flash_buffer_a[1] == 0x0555) && (flash_buffer_v[1] == 0x55) &&
 			(flash_buffer_a[2] == 0x0AAA) && (flash_buffer_v[2] == 0xA0))
 		{
-			int sector = prg_bank_a_mapped * 0x2000 / FLASH_SECTOR_SIZE;
+			//int sector = prg_bank_a_mapped * 0x2000 / FLASH_SECTOR_SIZE;
 			uint32 flash_addr = prg_bank_a_mapped * 0x2000 + (A % 0x8000);
 			if (SAVE_FLASH[flash_addr % SAVE_FLASH_SIZE] != 0xFF) {
 				FCEU_PrintError("Error: can't write to 0x%08x, flash sector is not erased.\n", flash_addr);

src/boards/fns.cpp

@@ -34,11 +34,13 @@ static uint8 *WRAM = NULL;
 static int kanji_pos, kanji_page, r40C0;
 static int IRQa, IRQCount;
 
+FCEU_MAYBE_UNUSED
 static DECLFW(MBWRAM) {
 	if (!(DRegs[3] & 0x10))
 		Page[A >> 11][A] = V;
 }
 
+FCEU_MAYBE_UNUSED
 static DECLFR(MAWRAM) {
 	if (DRegs[3] & 0x10)
 		return X.DB;

src/boards/mmc3.cpp

@@ -1376,6 +1376,7 @@ static DECLFW(M406IRQWrite) {
 	MMC3_IRQWrite((A & 0xFFFE) | ((A & 2) >> 1), V);
 }
 
+FCEU_MAYBE_UNUSED
 static DECLFW(M406Write) {
 }
 

src/fceu.cpp

@@ -726,7 +726,8 @@ extern unsigned int frameAdvHoldTimer;
 ///Skip may be passed in, if FRAMESKIP is #defined, to cause this to emulate more than one frame
 void FCEUI_Emulate(uint8 **pXBuf, int32 **SoundBuf, int32 *SoundBufSize, int skip) {
 	//skip initiates frame skip if 1, or frame skip and sound skip if 2
-	int r, ssize;
+	FCEU_MAYBE_UNUSED int r;
+	int ssize;
 
 	JustFrameAdvanced = false;
 

src/lua-engine.cpp

@@ -253,7 +253,7 @@ static const char *guiCallbackTable = "FCEU.GUI";
 static int frameAdvanceWaiting = FALSE;
 
 // We save our pause status in the case of a natural death.
-static int wasPaused = FALSE;
+//static int wasPaused = FALSE;
 
 // Transparency strength. 255=opaque, 0=so transparent it's invisible
 static int transparencyModifier = 255;
@@ -1635,7 +1635,7 @@ static void toCStringConverter(lua_State* L, int i, char*& ptr, int& remaining)
 	if(remaining <= 0)
 		return;
 
-	const char* str = ptr; // for debugging
+	//const char* str = ptr; // for debugging
 
 	// if there is a __tostring metamethod then call it
 	int usedMeta = luaL_callmeta(L, i, "__tostring");
@@ -2451,6 +2451,7 @@ LuaMemHookType MatchHookTypeToCPU(lua_State* L, LuaMemHookType hookType)
 		case LUAMEMHOOK_WRITE: return LUAMEMHOOK_WRITE_SUB;
 		case LUAMEMHOOK_READ: return LUAMEMHOOK_READ_SUB;
 		case LUAMEMHOOK_EXEC: return LUAMEMHOOK_EXEC_SUB;
+		default: return hookType;
 		}
 	}
 	return hookType;
@@ -2460,6 +2461,7 @@ static int memory_registerwrite(lua_State *L)
 {
 	return memory_registerHook(L, MatchHookTypeToCPU(L,LUAMEMHOOK_WRITE), 1);
 }
+FCEU_MAYBE_UNUSED
 static int memory_registerread(lua_State *L)
 {
 	return memory_registerHook(L, MatchHookTypeToCPU(L,LUAMEMHOOK_READ), 1);
@@ -2648,7 +2650,6 @@ static int input_get(lua_State *L) {
 
 		if (keyBuf)
 		{
-			int i=0;
 			char keyName[64];
 			const char *keyOut = nullptr;
 
@@ -3889,7 +3890,6 @@ static inline uint32 gui_getcolour_wrapped(lua_State *L, int offset, bool hasDef
 			lua_pushnil(L); // first key
 			int keyIndex = lua_gettop(L);
 			int valueIndex = keyIndex + 1;
-			bool first = true;
 			while(lua_next(L, offset))
 			{
 				bool keyIsString = (lua_type(L, keyIndex) == LUA_TSTRING);
@@ -4095,6 +4095,7 @@ static int gui_box(lua_State *L) {
 }
 
 // (old) gui.box(x1, y1, x2, y2, color)
+FCEU_MAYBE_UNUSED
 static int gui_box_old(lua_State *L) {
 
 	int x1,y1,x2,y2;
@@ -4424,6 +4425,7 @@ draw_outline:
 	}
 }
 
+FCEU_MAYBE_UNUSED
 static int strlinelen(const char* string)
 {
 	const char* s = string;
@@ -4434,6 +4436,7 @@ static int strlinelen(const char* string)
 	return s - string;
 }
 
+FCEU_MAYBE_UNUSED
 static void LuaDisplayString (const char *string, int y, int x, uint32 color, uint32 outlineColor)
 {
 	if(!string)
@@ -4601,7 +4604,7 @@ void LuaDrawTextTransWH(const char *str, size_t l, int &x, int y, uint32 color,
 		return;
 
 	size_t len = l;
-	int defaultAlpha = std::max<int>(0, std::min<int>(transparencyModifier, 255));
+	//int defaultAlpha = std::max<int>(0, std::min<int>(transparencyModifier, 255));
 	int diffx;
 	int diffy = std::max<int>(0, std::min<int>(7, LUA_SCREEN_HEIGHT - y));
 
@@ -4670,7 +4673,7 @@ void LuaDrawTextTransWH(const char *str, size_t l, int &x, int y, uint32 color,
 //  main HUD.
 static int gui_text(lua_State *L) {
 
-	extern int font_height;
+	//extern int font_height;
 	const char *msg;
 	int x, y;
 	size_t l;
@@ -5088,7 +5091,7 @@ static int taseditor_registermanual(lua_State *L)
 	if (!lua_isnil(L,1))
 		luaL_checktype(L, 1, LUA_TFUNCTION);
 
-	const char* caption = NULL;
+	FCEU_MAYBE_UNUSED const char* caption = NULL;
 	if (!lua_isnil(L, 2))
 		caption = lua_tostring(L, 2);
 
@@ -5474,10 +5477,10 @@ static int doPopup(lua_State *L, const char* deftype, const char* deficon) {
 	assert(iicon >= 0 && iicon <= 3);
 	if(!(iicon >= 0 && iicon <= 3)) iicon = 0;
 
+#ifdef __WIN_DRIVER__
 	static const char * const titles [] = {"Notice", "Question", "Warning", "Error"};
 	const char* answer = "ok";
 
-#ifdef __WIN_DRIVER__
 	static const int etypes [] = {MB_OK, MB_YESNO, MB_YESNOCANCEL, MB_OKCANCEL, MB_ABORTRETRYIGNORE};
 	static const int eicons [] = {MB_ICONINFORMATION, MB_ICONQUESTION, MB_ICONWARNING, MB_ICONERROR};
 	//StopSound(); //mbg merge 7/27/08
@@ -5912,6 +5915,7 @@ static int bitbit(lua_State *L)
 }
 
 // The function called periodically to ensure Lua doesn't run amok.
+FCEU_MAYBE_UNUSED
 static void FCEU_LuaHookFunction(lua_State *L, lua_Debug *dbg) {
 
 	if (numTries-- == 0) {

src/palette.cpp

@@ -87,6 +87,7 @@ pal *palo = NULL;
 	(type) (y + to_rgb [4] * i + to_rgb [5] * q)\
 )
 
+FCEU_MAYBE_UNUSED
 static void ApplyDeemphasisNTSC(int entry, u8& r, u8& g, u8& b)
 {
 				static float const to_float = 1.0f / 0xFF;
@@ -252,6 +253,7 @@ static void ApplyDeemphasisBisqwit(int entry, u8& r, u8& g, u8& b)
 }
 
 //classic algorithm
+FCEU_MAYBE_UNUSED
 static void ApplyDeemphasisClassic(int entry, u8& r, u8& g, u8& b)
 {
 	//DEEMPH BITS MAY BE ORDERED WRONG. PLEASE CHECK

src/pputile.inc

@@ -6,7 +6,7 @@ uint8 tmpd;
 #endif
 
 #ifndef PPUT_MMC5SP
-	uint8 zz;
+	FCEU_MAYBE_UNUSED uint8 zz;
 #else
 	uint8 xs, ys;
 	xs = X1;

src/types.h

@@ -143,6 +143,14 @@ typedef uint8 (*readfunc)(uint32 A);
 #define CTASSERT(x)  typedef char __assert ## y[(x) ? 1 : -1];
 #endif
 
+#define  FCEU_UNUSED(x)   (void)(x)
+
+#if __has_cpp_attribute(maybe_unused)
+#define  FCEU_MAYBE_UNUSED  [[maybe_unused]]
+#else
+#define  FCEU_MAYBE_UNUSED
+#endif
+
 #include "utils/endian.h"
 
 #endif

src/vsuni.cpp

@@ -160,6 +160,9 @@ void FCEU_VSUniPower(void) {
 	case GIPPU_RP2C04_0004:
 		default_palette_selection = GameInfo->vs_ppu;
 		break;
+	default:
+		// nothing todo
+		break;
 	}
 	if (GameInfo->vs_ppu == GIPPU_RC2C05_04) {
 		OldReadPPU = GetReadHandler(0x2002);

src/x6502.cpp

@@ -318,8 +318,8 @@ static uint8 ZNTable[256];
 #define LD_ZP(op)  {uint8 A; uint8 x; GetZP(A); x=RdRAM(A); op; break;}
 #define LD_ZPX(op)  {uint8 A; uint8 x; GetZPI(A,_X); x=RdRAM(A); op; break;}
 #define LD_ZPY(op)  {uint8 A; uint8 x; GetZPI(A,_Y); x=RdRAM(A); op; break;}
-#define LD_AB(op)  {unsigned int A; uint8 x; GetAB(A); x=RdMem(A); op; break; }
-#define LD_ABI(reg,op)  {unsigned int A; uint8 x; GetABIRD(A,reg); x=RdMem(A); op; break;}
+#define LD_AB(op)  {unsigned int A; FCEU_MAYBE_UNUSED uint8 x; GetAB(A); x=RdMem(A); op; break; }
+#define LD_ABI(reg,op)  {unsigned int A; FCEU_MAYBE_UNUSED uint8 x; GetABIRD(A,reg); x=RdMem(A); op; break;}
 #define LD_ABX(op)  LD_ABI(_X,op)
 #define LD_ABY(op)  LD_ABI(_Y,op)
 #define LD_IX(op)  {unsigned int A; uint8 x; GetIX(A); x=RdMem(A); op; break;}