Prefer [[maybe_unused]] over UNUSED2

`[[maybe_unused]]` is in the C++ standard.

source/lib/debug.h

@@ -301,7 +301,7 @@ Status debug_WriteCrashlog(const char* text);
  * (we do not provide an MFC-style VERIFY macro because the distinction
  * between ENSURE and VERIFY is unclear. to always run code but only
  * check for success in debug builds without raising unused-variable warnings,
- * use ASSERT + UNUSED2.)
+ * use [[maybe_unused]].)
  **/
 #define ASSERT(expr) ENSURE(expr)
 #ifdef NDEBUG

source/lib/debug_stl.cpp

@@ -552,17 +552,11 @@ template<class T> bool get_container_info(const T& t, size_t size, size_t el_siz
 // return number of elements and an iterator (any data it needs is stored in
 // it_mem, which must hold DEBUG_STL_MAX_ITERATOR_SIZE bytes).
 // returns 0 on success or an StlContainerError.
-Status debug_stl_get_container_info(const wchar_t* type_name, const u8* p, size_t size,
-	size_t el_size, size_t* el_count, DebugStlIterator* el_iterator, void* it_mem)
+Status debug_stl_get_container_info([[maybe_unused]] const wchar_t* type_name, [[maybe_unused]] const u8* p,
+	[[maybe_unused]] size_t size, [[maybe_unused]] size_t el_size, [[maybe_unused]] size_t* el_count,
+	[[maybe_unused]] DebugStlIterator* el_iterator, [[maybe_unused]] void* it_mem)
 {
 #if MSC_VERSION
-	UNUSED2(type_name);
-	UNUSED2(p);
-	UNUSED2(size);
-	UNUSED2(el_size);
-	UNUSED2(el_count);
-	UNUSED2(el_iterator);
-	UNUSED2(it_mem);
 	return ERR::STL_CNT_UNSUPPORTED;	// NOWARN
 #else
 

source/lib/file/archive/codec_zlib.cpp

@@ -37,14 +37,12 @@
 class Codec_ZLib : public ICodec
 {
 public:
-	u32 UpdateChecksum(u32 checksum, const u8* in, size_t inSize) const
+	u32 UpdateChecksum([[maybe_unused]] u32 checksum, [[maybe_unused]] const u8* in,
+		[[maybe_unused]] size_t inSize) const
 	{
 #if CODEC_COMPUTE_CHECKSUM
 		return (u32)crc32(checksum, in, (uInt)inSize);
 #else
-		UNUSED2(checksum);
-		UNUSED2(in);
-		UNUSED2(inSize);
 		return 0;
 #endif
 	}

source/lib/file/io/io.cpp

@@ -39,7 +39,7 @@ namespace io {
 // note that the Windows aio implementation requires buffers, sizes and
 // offsets to be sector-aligned.
 
-Status Issue(aiocb& cb, size_t queueDepth)
+Status Issue(aiocb& cb, [[maybe_unused]] size_t queueDepth)
 {
 #if CONFIG2_FILE_ENABLE_AIO
 	if(queueDepth > 1)
@@ -49,8 +49,6 @@ Status Issue(aiocb& cb, size_t queueDepth)
 			WARN_RETURN(StatusFromErrno());
 	}
 	else
-#else
-	UNUSED2(queueDepth);
 #endif
 	{
 		ENSURE(lseek(cb.aio_fildes, cb.aio_offset, SEEK_SET) == cb.aio_offset);
@@ -67,7 +65,7 @@ Status Issue(aiocb& cb, size_t queueDepth)
 }
 
 
-Status WaitUntilComplete(aiocb& cb, size_t queueDepth)
+Status WaitUntilComplete([[maybe_unused]] aiocb& cb, [[maybe_unused]] size_t queueDepth)
 {
 #if CONFIG2_FILE_ENABLE_AIO
 	if(queueDepth > 1)
@@ -94,9 +92,6 @@ SUSPEND_AGAIN:
 		}
 		cb.aio_nbytes = (size_t)bytesTransferred;
 	}
-#else
-	UNUSED2(cb);
-	UNUSED2(queueDepth);
 #endif
 
 	return INFO::OK;

source/lib/ogl.cpp

@@ -24,7 +24,6 @@
 
 #include "lib/ogl.h"
 
-#include "lib/code_annotation.h"
 #include "lib/config2.h"
 #include "lib/debug.h"
 #include "lib/external_libraries/libsdl.h"
@@ -518,7 +517,7 @@ bool ogl_Init(void* (load)(const char*))
 
 void ogl_SetVsyncEnabled(bool enabled)
 {
-	const int interval = enabled ? 1 : 0;
+	[[maybe_unused]] const int interval = enabled ? 1 : 0;
 #if !CONFIG2_GLES && OS_WIN
 	if (ogl_HaveExtension("WGL_EXT_swap_control"))
 		wglSwapIntervalEXT(interval);
@@ -526,10 +525,6 @@ void ogl_SetVsyncEnabled(bool enabled)
 #if defined(SDL_VIDEO_DRIVER_X11)
 	if (GLXVersion && ogl_HaveExtension("GLX_SGI_swap_control"))
 		glXSwapIntervalSGI(interval);
-#else
-	UNUSED2(interval);
 #endif
-#else
-	UNUSED2(interval);
 #endif
 }

source/lib/sysdep/arch/x86_x64/apic.cpp

@@ -37,8 +37,8 @@ ApicId GetApicId()
 	regs.eax = 1;
 	// note: CPUID function 1 is always supported, but only processors with
 	// an xAPIC (e.g. P4/Athlon XP) will return a nonzero ID.
-	bool ok = x86_x64::cpuid(&regs);
-	ASSERT(ok); UNUSED2(ok);
+	[[maybe_unused]] bool ok = x86_x64::cpuid(&regs);
+	ASSERT(ok);
 	const u8 apicId = (u8)bits(regs.ebx, 24, 31);
 	return apicId;
 }

source/lib/sysdep/os/win/tests/test_wdbg_sym.h

@@ -138,15 +138,15 @@ class TestWdbgSym : public CxxTest::TestSuite
 			char s3;
 		}
 		Small;
-		Small small__ = { 0x55, 0xaa, -1 }; UNUSED2(small__);
+		[[maybe_unused]] Small small__ = { 0x55, 0xaa, -1 };
 
 		struct Large
 		{
 			u8 large_member_u8;
 			std::string large_member_string;
 			double large_member_double;
-		}
-		large = { 0xff, "large struct string", 123456.0 }; UNUSED2(large);
+		};
+		[[maybe_unused]] Large large = { 0xff, "large struct string", 123456.0 };
 
 
 		class Base
@@ -235,14 +235,15 @@ class TestWdbgSym : public CxxTest::TestSuite
 
 	// also exercises all basic types because we need to display some values
 	// anyway (to see at a glance whether symbol engine addrs are correct)
-	static void m_test_addrs(int p_int, double p_double, char* p_pchar, uintptr_t p_uintptr)
+	static void m_test_addrs([[maybe_unused]] int p_int, [[maybe_unused]] double p_double,
+		[[maybe_unused]] char* p_pchar, [[maybe_unused]] uintptr_t p_uintptr)
 	{
-		size_t l_uint = 0x1234;
-		bool l_bool = true; UNUSED2(l_bool);
-		wchar_t l_wchars[] = L"wchar string";
-		enum TestEnum { VAL1=1, VAL2=2 } l_enum = VAL1;
-		u8 l_u8s[] = { 1,2,3,4 };
-		void (*l_funcptr)(void) = m_test_stl;
+		[[maybe_unused]] size_t l_uint = 0x1234;
+		[[maybe_unused]] bool l_bool = true;
+		[[maybe_unused]] wchar_t l_wchars[] = L"wchar string";
+		[[maybe_unused]] enum TestEnum { VAL1=1, VAL2=2 } l_enum = VAL1;
+		[[maybe_unused]] u8 l_u8s[] = { 1,2,3,4 };
+		[[maybe_unused]] void (*l_funcptr)(void) = m_test_stl;
 
 		static double s_double = -2.718;
 		static char s_chars[] = {'c','h','a','r','s',0};
@@ -262,25 +263,15 @@ class TestWdbgSym : public CxxTest::TestSuite
 		debug_printf("l_enum    addr=%p val=%d\n", &l_enum, l_enum);
 		debug_printf("l_u8s     addr=%p val=%d\n", &l_u8s, l_u8s);
 		debug_printf("l_funcptr addr=%p val=%p\n", &l_funcptr, l_funcptr);
-#else
-		UNUSED2(p_uintptr);
-		UNUSED2(p_pchar);
-		UNUSED2(p_double);
-		UNUSED2(p_int);
-		UNUSED2(l_funcptr);
-		UNUSED2(l_enum);
-		UNUSED2(l_uint);
-		UNUSED2(l_u8s);
-		UNUSED2(l_wchars);
 #endif
 
 		m_test_stl();
 
-		int uninit_int; UNUSED2(uninit_int);
-		float uninit_float; UNUSED2(uninit_float);
-		double uninit_double; UNUSED2(uninit_double);
-		bool uninit_bool; UNUSED2(uninit_bool);
-		HWND uninit_hwnd; UNUSED2(uninit_hwnd);
+		[[maybe_unused]] int uninit_int;
+		[[maybe_unused]] float uninit_float;
+		[[maybe_unused]] double uninit_double;
+		[[maybe_unused]] bool uninit_bool;
+		[[maybe_unused]] HWND uninit_hwnd;
 	}
 
 #pragma optimize("", on)

source/lib/sysdep/os/win/wnuma.cpp

@@ -473,7 +473,8 @@ bool numa_IsMemoryInterleaved()
 
 #if 0
 
-static bool VerifyPages(void* mem, size_t size, size_t pageSize, size_t node)
+static bool VerifyPages([[maybe_unused]] void* mem, [[maybe_unused]] size_t size,
+	[[maybe_unused]] size_t pageSize, [[maybe_unused]] size_t node)
 {
 	WUTIL_FUNC(pQueryWorkingSetEx, BOOL, (HANDLE, PVOID, DWORD));
 	WUTIL_IMPORT_KERNEL32(QueryWorkingSetEx, pQueryWorkingSetEx);
@@ -510,11 +511,6 @@ static bool VerifyPages(void* mem, size_t size, size_t pageSize, size_t node)
 	}
 
 	delete[] wsi;
-#else
-	UNUSED2(mem);
-	UNUSED2(size);
-	UNUSED2(pageSize);
-	UNUSED2(node);
 #endif
 
 	return true;

source/network/NMTCreator.h

@@ -146,15 +146,13 @@ public: \
 size_t _nm::GetSerializedLength() const \
 { \
 	size_t ret=_base::GetSerializedLength(); \
-	const _nm *thiz=this;\
-	UNUSED2(thiz);	// preempt any "unused" warning
+	[[maybe_unused]] const _nm *thiz=this;
 
 #define NMT_START_ARRAY(_nm) \
 	std::vector <ARRAY_STRUCT_PREFIX(_nm)>::const_iterator it=_nm.begin(); \
 	while (it != _nm.end()) \
 	{ \
-		const ARRAY_STRUCT_PREFIX(_nm) *thiz=&*it;\
-		UNUSED2(thiz);	// preempt any "unused" warning
+		[[maybe_unused]] const ARRAY_STRUCT_PREFIX(_nm) *thiz=&*it;
 
 #define NMT_END_ARRAY() \
 		++it; \
@@ -191,15 +189,13 @@ u8 *_nm::Serialize(u8 *buffer) const \
 { \
 	/*printf("In " #_nm "::Serialize()\n");*/ \
 	u8 *pos=_base::Serialize(buffer); \
-	const _nm *thiz=this;\
-	UNUSED2(thiz);	// preempt any "unused" warning
+	[[maybe_unused]] const _nm *thiz=this;
 
 #define NMT_START_ARRAY(_nm) \
 	std::vector <ARRAY_STRUCT_PREFIX(_nm)>::const_iterator it=_nm.begin(); \
 	while (it != _nm.end()) \
 	{ \
-		const ARRAY_STRUCT_PREFIX(_nm) *thiz=&*it;\
-		UNUSED2(thiz);	// preempt any "unused" warning
+		[[maybe_unused]] const ARRAY_STRUCT_PREFIX(_nm) *thiz=&*it;
 
 #define NMT_END_ARRAY() \
 		++it; \
@@ -239,16 +235,15 @@ const u8 *_nm::Deserialize(const u8 *pos, const u8 *end) \
 { \
 	pos=_base::Deserialize(pos, end); \
 	if (pos == NULL) BAIL_DESERIALIZER;\
-	_nm *thiz=this; \
-	/*printf("In Deserialize" #_nm "\n"); */\
-	UNUSED2(thiz);	// preempt any "unused" warning
+	[[maybe_unused]] _nm *thiz=this; \
+	/*printf("In Deserialize" #_nm "\n"); */
 
 
 #define NMT_START_ARRAY(_nm) \
 	while (pos < end) \
 	{ \
-		ARRAY_STRUCT_PREFIX(_nm) *thiz=&*_nm.insert(_nm.end(), ARRAY_STRUCT_PREFIX(_nm)());\
-		UNUSED2(thiz);	// preempt any "unused" warning
+		[[maybe_unused]] ARRAY_STRUCT_PREFIX(_nm) *thiz = \
+			&*_nm.insert(_nm.end(), ARRAY_STRUCT_PREFIX(_nm)());
 
 #define NMT_END_ARRAY() \
 	}
@@ -289,8 +284,7 @@ CStr _nm::ToString() const \
 CStr _nm::ToStringRaw() const \
 { \
 	CStr ret; \
-	const _nm *thiz=this;\
-	UNUSED2(thiz);	// preempt any "unused" warning
+	[[maybe_unused]] const _nm *thiz=this;
 
 #define START_NMT_CLASS_DERIVED(_base, _nm, _tp) \
 CStr _nm::ToString() const \
@@ -301,8 +295,7 @@ CStr _nm::ToString() const \
 CStr _nm::ToStringRaw() const \
 { \
 	CStr ret=_base::ToStringRaw() + ", "; \
-	const _nm *thiz=this;\
-	UNUSED2(thiz);	// preempt any "unused" warning
+	[[maybe_unused]] const _nm *thiz=this;
 
 #define NMT_START_ARRAY(_nm) \
 	ret+=#_nm ": { "; \
@@ -310,8 +303,7 @@ CStr _nm::ToStringRaw() const \
 	while (it != _nm.end()) \
 	{ \
 		ret+=" { "; \
-		const ARRAY_STRUCT_PREFIX(_nm) *thiz=&*it;\
-		UNUSED2(thiz);	// preempt any "unused" warning
+		[[maybe_unused]] const ARRAY_STRUCT_PREFIX(_nm) *thiz=&*it;
 
 #define NMT_END_ARRAY() \
 		++it; \

source/network/NetMessageSim.cpp

@@ -46,7 +46,7 @@ public:
 	{
 	}
 
-	void Put(const char* name, const u8* data, size_t len)
+	void Put([[maybe_unused]] const char* name, const u8* data, size_t len)
 	{
 		#if DEBUG_SERIALIZER_ANNOTATE
 			std::string tag = "<";
@@ -54,8 +54,6 @@ public:
 			tag.append(">");
 			memcpy(m_Buffer, tag.c_str(), tag.length());
 			m_Buffer += tag.length();
-		#else
-			UNUSED2(name);
 		#endif
 		memcpy(m_Buffer, data, len);
 		m_Buffer += len;
@@ -89,13 +87,11 @@ public:
 	{
 	}
 
-	void Put(const char* name, const u8* /*data*/, size_t len)
+	void Put([[maybe_unused]] const char* name, const u8* /*data*/, size_t len)
 	{
 		#if DEBUG_SERIALIZER_ANNOTATE
 		m_Length += 2;	// '<' and '>'
 		m_Length += strlen(name);
-		#else
-			UNUSED2(name);
 		#endif
 		m_Length += len;
 	}

source/ps/GameSetup/Paths.cpp

@@ -184,11 +184,10 @@ Paths::Paths(const CmdLineArgs& args)
 #endif
 }
 
-/*static*/ OsPath Paths::RootData(const OsPath& argv0)
+/*static*/ OsPath Paths::RootData([[maybe_unused]] const OsPath& argv0)
 {
 
 #ifdef INSTALLED_DATADIR
-	UNUSED2(argv0);
 	return OsPath(STRINGIZE(INSTALLED_DATADIR))/"";
 #else
 

source/ps/TouchInput.cpp

@@ -1,4 +1,4 @@
-/* Copyright (C) 2024 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -182,10 +182,8 @@ void CTouchInput::Frame()
 	}
 }
 
-InReaction CTouchInput::HandleEvent(const SDL_Event_* ev)
+InReaction CTouchInput::HandleEvent([[maybe_unused]] const SDL_Event_* ev)
 {
-	UNUSED2(ev); // may be unused depending on #ifs
-
 	if (!IsEnabled())
 		return IN_PASS;
 

source/renderer/backend/gl/Buffer.cpp

@@ -59,7 +59,7 @@ GLenum GetTargetFromBufferType(const IBuffer::Type type)
 
 // static
 std::unique_ptr<CBuffer> CBuffer::Create(
-	CDevice* device, const char* name,
+	CDevice* device, [[maybe_unused]] const char* name,
 	const Type type, const uint32_t size, const uint32_t usage)
 {
 	ENSURE(type == Type::VERTEX || type == Type::INDEX || type == Type::UNIFORM);
@@ -77,8 +77,6 @@ std::unique_ptr<CBuffer> CBuffer::Create(
 	{
 		glObjectLabel(GL_BUFFER, buffer->m_Handle, -1, name);
 	}
-#else
-	UNUSED2(name);
 #endif
 	glBindBufferARB(target, 0);
 	return buffer;

source/renderer/backend/gl/DeviceCommandContext.cpp

@@ -864,18 +864,13 @@ void CDeviceCommandContext::SetGraphicsPipelineStateImpl(
 
 void CDeviceCommandContext::BlitFramebuffer(
 	IFramebuffer* srcFramebuffer, IFramebuffer* dstFramebuffer,
-	const Rect& sourceRegion, const Rect& destinationRegion,
-	const Sampler::Filter filter)
+	[[maybe_unused]] const Rect& sourceRegion, [[maybe_unused]] const Rect& destinationRegion,
+	[[maybe_unused]] const Sampler::Filter filter)
 {
 	ENSURE(!m_InsideFramebufferPass);
-	CFramebuffer* destinationFramebuffer = dstFramebuffer->As<CFramebuffer>();
-	CFramebuffer* sourceFramebuffer = srcFramebuffer->As<CFramebuffer>();
+	[[maybe_unused]] CFramebuffer* destinationFramebuffer = dstFramebuffer->As<CFramebuffer>();
+	[[maybe_unused]] CFramebuffer* sourceFramebuffer = srcFramebuffer->As<CFramebuffer>();
 #if CONFIG2_GLES
-	UNUSED2(destinationFramebuffer);
-	UNUSED2(sourceFramebuffer);
-	UNUSED2(destinationRegion);
-	UNUSED2(sourceRegion);
-	UNUSED2(filter);
 	debug_warn("CDeviceCommandContext::BlitFramebuffer is not implemented for GLES");
 #else
 	// Source framebuffer should not be backbuffer.
@@ -1188,7 +1183,7 @@ void CDeviceCommandContext::DrawIndexed(
 }
 
 void CDeviceCommandContext::DrawInstanced(
-	const uint32_t firstVertex, const uint32_t vertexCount,
+	[[maybe_unused]] const uint32_t firstVertex, const uint32_t vertexCount,
 	const uint32_t firstInstance, const uint32_t instanceCount)
 {
 	ENSURE(m_Device->GetCapabilities().instancing);
@@ -1200,7 +1195,6 @@ void CDeviceCommandContext::DrawInstanced(
 	m_ShaderProgram->AssertPointersBound();
 #if CONFIG2_GLES
 	ENSURE(!m_Device->GetCapabilities().instancing);
-	UNUSED2(firstVertex);
 #else
 	glDrawArraysInstancedARB(GL_TRIANGLES, firstVertex, vertexCount, instanceCount);
 #endif
@@ -1209,7 +1203,7 @@ void CDeviceCommandContext::DrawInstanced(
 
 void CDeviceCommandContext::DrawIndexedInstanced(
 	const uint32_t firstIndex, const uint32_t indexCount,
-	const uint32_t firstInstance, const uint32_t instanceCount,
+	const uint32_t firstInstance, [[maybe_unused]] const uint32_t instanceCount,
 	const int32_t vertexOffset)
 {
 	ENSURE(m_Device->GetCapabilities().instancing);
@@ -1229,7 +1223,6 @@ void CDeviceCommandContext::DrawIndexedInstanced(
 	// in Mesa 7.10 swrast with index VBOs).
 #if CONFIG2_GLES
 	ENSURE(!m_Device->GetCapabilities().instancing);
-	UNUSED2(instanceCount);
 #else
 	glDrawElementsInstancedARB(GL_TRIANGLES, indexCount, GL_UNSIGNED_SHORT,
 		static_cast<const void*>((static_cast<const uint8_t*>(m_IndexBufferData) + sizeof(uint16_t) * firstIndex)),
@@ -1240,7 +1233,7 @@ void CDeviceCommandContext::DrawIndexedInstanced(
 
 void CDeviceCommandContext::DrawIndexedInRange(
 	const uint32_t firstIndex, const uint32_t indexCount,
-	const uint32_t start, const uint32_t end)
+	[[maybe_unused]] const uint32_t start, [[maybe_unused]] const uint32_t end)
 {
 	ENSURE(m_ShaderProgram);
 	ENSURE(m_InsidePass);
@@ -1253,8 +1246,6 @@ void CDeviceCommandContext::DrawIndexedInRange(
 	// Draw with DrawRangeElements where available, since it might be more
 	// efficient for slow hardware.
 #if CONFIG2_GLES
-	UNUSED2(start);
-	UNUSED2(end);
 	glDrawElements(GL_TRIANGLES, indexCount, GL_UNSIGNED_SHORT, indices);
 #else
 	glDrawRangeElementsEXT(GL_TRIANGLES, start, end, indexCount, GL_UNSIGNED_SHORT, indices);
@@ -1276,9 +1267,9 @@ void CDeviceCommandContext::EndComputePass()
 }
 
 void CDeviceCommandContext::Dispatch(
-	const uint32_t groupCountX,
-	const uint32_t groupCountY,
-	const uint32_t groupCountZ)
+	[[maybe_unused]] const uint32_t groupCountX,
+	[[maybe_unused]] const uint32_t groupCountY,
+	[[maybe_unused]] const uint32_t groupCountZ)
 {
 #if !CONFIG2_GLES
 	ENSURE(m_InsideComputePass);
@@ -1290,16 +1281,12 @@ void CDeviceCommandContext::Dispatch(
 		glMemoryBarrier(
 			GL_SHADER_IMAGE_ACCESS_BARRIER_BIT | GL_TEXTURE_FETCH_BARRIER_BIT | GL_TEXTURE_UPDATE_BARRIER_BIT | GL_FRAMEBUFFER_BARRIER_BIT );
 	}
-#else
-	UNUSED2(groupCountX);
-	UNUSED2(groupCountY);
-	UNUSED2(groupCountZ);
 #endif
 }
 
 void CDeviceCommandContext::InsertMemoryBarrier(
-	const uint32_t /*srcStageMask*/, const uint32_t dstStageMask,
-	const uint32_t srcAccessMask, const uint32_t dstAccessMask)
+	const uint32_t /*srcStageMask*/, [[maybe_unused]] const uint32_t dstStageMask,
+	[[maybe_unused]] const uint32_t srcAccessMask, [[maybe_unused]] const uint32_t dstAccessMask)
 {
 #if !CONFIG2_GLES
 	ENSURE(!m_InsideFramebufferPass);
@@ -1323,10 +1310,6 @@ void CDeviceCommandContext::InsertMemoryBarrier(
 	}
 	if (barriers)
 		glMemoryBarrier(barriers);
-#else
-	UNUSED2(dstStageMask);
-	UNUSED2(srcAccessMask);
-	UNUSED2(dstAccessMask);
 #endif
 }
 
@@ -1372,7 +1355,8 @@ void CDeviceCommandContext::SetTexture(const int32_t bindingSlot, ITexture* text
 	BindTexture(unit, textureUnit.target, texture->As<CTexture>()->GetHandle());
 }
 
-void CDeviceCommandContext::SetStorageTexture(const int32_t bindingSlot, ITexture* texture)
+void CDeviceCommandContext::SetStorageTexture([[maybe_unused]] const int32_t bindingSlot,
+	[[maybe_unused]] ITexture* texture)
 {
 #if !CONFIG2_GLES
 	ENSURE(m_ShaderProgram);
@@ -1386,13 +1370,11 @@ void CDeviceCommandContext::SetStorageTexture(const int32_t bindingSlot, ITextur
 	ENSURE(textureUnit.type == GL_IMAGE_2D);
 	ENSURE(texture->GetFormat() == Format::R8G8B8A8_UNORM);
 	glBindImageTexture(textureUnit.unit, texture->As<CTexture>()->GetHandle(), 0, GL_FALSE, 0, GL_READ_WRITE, GL_RGBA8);
-#else
-	UNUSED2(bindingSlot);
-	UNUSED2(texture);
 #endif
 }
 
-void CDeviceCommandContext::SetStorageBuffer(const int32_t bindingSlot, IBuffer* buffer)
+void CDeviceCommandContext::SetStorageBuffer([[maybe_unused]] const int32_t bindingSlot,
+	[[maybe_unused]] IBuffer* buffer)
 {
 #if !CONFIG2_GLES
 	if (bindingSlot < 0)
@@ -1401,9 +1383,6 @@ void CDeviceCommandContext::SetStorageBuffer(const int32_t bindingSlot, IBuffer*
 	ENSURE(buffer);
 	ENSURE(buffer->GetUsage() & Renderer::Backend::IBuffer::Usage::STORAGE);
 	glBindBufferBase(GL_SHADER_STORAGE_BUFFER, m_ShaderProgram->GetStorageBuffer(bindingSlot), buffer->As<CBuffer>()->GetHandle());
-#else
-	UNUSED2(bindingSlot);
-	UNUSED2(buffer);
 #endif
 }
 

source/renderer/backend/gl/Framebuffer.cpp

@@ -38,7 +38,7 @@ namespace GL
 
 // static
 std::unique_ptr<CFramebuffer> CFramebuffer::Create(
-	CDevice* device, const char* name, SColorAttachment* colorAttachment,
+	CDevice* device, [[maybe_unused]] const char* name, SColorAttachment* colorAttachment,
 	SDepthStencilAttachment* depthStencilAttachment)
 {
 	ENSURE(colorAttachment || depthStencilAttachment);
@@ -143,8 +143,6 @@ std::unique_ptr<CFramebuffer> CFramebuffer::Create(
 	{
 		glObjectLabel(GL_FRAMEBUFFER, framebuffer->m_Handle, -1, name);
 	}
-#else
-	UNUSED2(name);
 #endif
 
 	const GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);

source/renderer/backend/gl/ShaderProgram.cpp

@@ -1254,7 +1254,7 @@ public:
 	void VertexAttribPointer(
 		const VertexAttributeStream stream, const Format format,
 		const uint32_t offset, const uint32_t stride,
-		const VertexAttributeRate rate, const void* data) override
+		[[maybe_unused]] const VertexAttributeRate rate, const void* data) override
 	{
 		const int attributeLocation = GetAttributeLocationFromStream(m_Device, stream);
 		std::vector<int>::const_iterator it =
@@ -1268,7 +1268,6 @@ public:
 			attributeLocation, size, type, normalized, stride, static_cast<const u8*>(data) + offset);
 #if CONFIG2_GLES
 		ENSURE(!m_Device->GetCapabilities().instancing);
-		UNUSED2(rate);
 #else
 		if (rate == VertexAttributeRate::PER_INSTANCE)
 			ENSURE(m_Device->GetCapabilities().instancing);

source/scriptinterface/FunctionWrapper.h

@@ -104,7 +104,8 @@ private:
 	 * @param wentOk - true if the conversion succeeded and wentOk was true before, false otherwise.
 	 */
 	template<size_t idx, typename T>
-	static T DoConvertFromJS(const ScriptRequest& rq, JS::CallArgs& args, bool& wentOk)
+	static T DoConvertFromJS([[maybe_unused]] const ScriptRequest& rq,
+		[[maybe_unused]] JS::CallArgs& args, [[maybe_unused]] bool& wentOk)
 	{
 		// No need to convert JS values.
 		if constexpr (std::is_same_v<T, JS::HandleValue>)
@@ -114,11 +115,7 @@ private:
 			if (idx >= args.length())
 				return JS::UndefinedHandleValue;
 			else
-			{
-				// GCC (at least < 9) & VS17 prints warnings if arguments are not used in some constexpr branch.
-				UNUSED2(rq); UNUSED2(args); UNUSED2(wentOk);
 				return args[idx]; // This passes the null handle value if idx is beyond the length of args.
-			}
 		}
 		else
 		{
@@ -185,14 +182,10 @@ private:
 	 * Wrap std::apply for the case where we have an object method or a regular function.
 	 */
 	template <auto callable, typename T, typename tuple>
-	static typename args_info<callable>::return_type call(T* object, tuple& args)
+	static typename args_info<callable>::return_type call([[maybe_unused]] T* object, tuple& args)
 	{
 		if constexpr(std::is_same_v<T, void>)
-		{
-			// GCC (at least < 9) & VS17 prints warnings if arguments are not used in some constexpr branch.
-			UNUSED2(object);
 			return std::apply(callable, args);
-		}
 		else
 			return std::apply(callable, std::tuple_cat(std::forward_as_tuple(*object), args));
 	}
@@ -224,7 +217,8 @@ private:
 	 * This could be worked around with more templates, but it doesn't seem particularly worth doing.
 	 */
 	template<typename R, typename ...Args>
-	static bool Call_(const ScriptRequest& rq, JS::HandleValue val, const char* name, R& ret, const Args&... args)
+	static bool Call_(const ScriptRequest& rq, JS::HandleValue val, const char* name,
+		[[maybe_unused]] R& ret, const Args&... args)
 	{
 		JS::RootedObject obj(rq.cx);
 		if (!JS_ValueToObject(rq.cx, val, &obj) || !obj)
@@ -251,8 +245,6 @@ private:
 				if (success)
 					success = Script::FromJSVal(rq, jsRet, ret);
 			}
-			else
-				UNUSED2(ret); // VS2017 complains.
 		}
 		// Even if everything succeeded, there could be pending exceptions
 		return !ScriptException::CatchPending(rq) && success;

source/simulation2/serialization/StdDeserializer.cpp

@@ -60,7 +60,7 @@ void CStdDeserializer::TraceMember(JSTracer *trc)
 		JS::TraceEdge(trc, &backref, "StdDeserializer::m_ScriptBackrefs");
 }
 
-void CStdDeserializer::Get(const char* name, u8* data, size_t len)
+void CStdDeserializer::Get([[maybe_unused]] const char* name, u8* data, size_t len)
 {
 #if DEBUG_SERIALIZER_ANNOTATE
 	std::string strName;
@@ -75,8 +75,6 @@ void CStdDeserializer::Get(const char* name, u8* data, size_t len)
 			strName += c;
 	}
 	ENSURE(strName == name);
-#else
-	UNUSED2(name);
 #endif
 	m_Stream.read((char*)data, (std::streamsize)len);
 	if (!m_Stream.good())

source/simulation2/serialization/StdSerializer.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2017 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -35,14 +35,12 @@ public:
 		m_Stream.flush();
 	}
 
-	void Put(const char* name, const u8* data, size_t len)
+	void Put([[maybe_unused]] const char* name, const u8* data, size_t len)
 	{
 #if DEBUG_SERIALIZER_ANNOTATE
 		m_Stream.put('<');
 		m_Stream.write(name, strlen(name));
 		m_Stream.put('>');
-#else
-		UNUSED2(name);
 #endif
 		m_Stream.write((const char*)data, (std::streamsize)len);
 	}

source/soundmanager/scripting/SoundGroup.cpp

@@ -128,12 +128,10 @@ CSoundGroup::~CSoundGroup()
 	ReleaseGroup();
 }
 
-float CSoundGroup::RadiansOffCenter(const CVector3D& position, bool& onScreen, float& itemRollOff)
+float CSoundGroup::RadiansOffCenter([[maybe_unused]] const CVector3D& position,
+	[[maybe_unused]] bool& onScreen, [[maybe_unused]] float& itemRollOff)
 {
 #if !CONFIG2_AUDIO
-        UNUSED2(position);
-        UNUSED2(onScreen);
-        UNUSED2(itemRollOff);
 	return 0.f;
 #else
 	const int screenWidth = g_Game->GetView()->GetCamera()->GetViewPort().m_Width;
@@ -181,13 +179,10 @@ float CSoundGroup::RadiansOffCenter(const CVector3D& position, bool& onScreen, f
 #endif // !CONFIG2_AUDIO
 }
 
-void CSoundGroup::UploadPropertiesAndPlay(size_t index, const CVector3D& position, entity_id_t source)
+void CSoundGroup::UploadPropertiesAndPlay([[maybe_unused]] size_t index,
+	[[maybe_unused]] const CVector3D& position, [[maybe_unused]] entity_id_t source)
 {
-#if !CONFIG2_AUDIO
-	UNUSED2(index);
-	UNUSED2(position);
-	UNUSED2(source);
-#else
+#if CONFIG2_AUDIO
 	if (!g_SoundManager)
 		return;
 

source/tools/atlas/GameInterface/Handlers/CameraCtrlHandlers.cpp

@@ -1,4 +1,4 @@
-/* Copyright (C) 2024 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -57,8 +57,6 @@ MESSAGEHANDLER(CameraReset)
 	}
 
 	g_Game->GetView()->ResetCameraTarget(target);
-
-	UNUSED2(msg);
 }
 
 MESSAGEHANDLER(ScrollConstant)

source/tools/atlas/GameInterface/Handlers/CinemaHandler.cpp

@@ -1,4 +1,4 @@
-/* Copyright (C) 2024 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -534,7 +534,6 @@ QUERYHANDLER(PickAxis)
 
 MESSAGEHANDLER(ClearPathNodePreview)
 {
-	UNUSED2(msg);
 	g_AtlasGameLoop->view->SetParam(L"movetool", false);
 }
 

source/tools/atlas/GameInterface/Handlers/CommandHandlers.cpp

@@ -43,19 +43,16 @@ MESSAGEHANDLER(DoCommand)
 
 MESSAGEHANDLER(UndoCommand)
 {
-	UNUSED2(msg);
 	GetCommandProc().Undo();
 }
 
 MESSAGEHANDLER(RedoCommand)
 {
-	UNUSED2(msg);
 	GetCommandProc().Redo();
 }
 
 MESSAGEHANDLER(MergeCommand)
 {
-	UNUSED2(msg);
 	GetCommandProc().Merge();
 }
 

source/tools/atlas/GameInterface/Handlers/GraphicsSetupHandlers.cpp

@@ -1,4 +1,4 @@
-/* Copyright (C) 2024 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -72,8 +72,6 @@ std::optional<ScriptInterface> g_ScriptInterface;
 
 MESSAGEHANDLER(Init)
 {
-	UNUSED2(msg);
-
 	g_Quickstart = true;
 
 	InitVfs(g_AtlasGameLoop->args);
@@ -98,15 +96,11 @@ MESSAGEHANDLER(InitAppWindow)
 {
 #if OS_WIN
 	wutil_SetAppWindow(msg->handle);
-#else
-	UNUSED2(msg);
 #endif
 }
 
 MESSAGEHANDLER(InitSDL)
 {
-	UNUSED2(msg);
-
 	// When using GLX (Linux), SDL has to load the GL library to find
 	// glXGetProcAddressARB before it can load any extensions.
 	// When running in Atlas, we skip the SDL video initialisation code
@@ -128,8 +122,6 @@ MESSAGEHANDLER(InitSDL)
 
 MESSAGEHANDLER(InitGraphics)
 {
-	UNUSED2(msg);
-
 	g_VideoMode.CreateBackendDevice(false);
 
 	g_VideoMode.GetBackendDevice()->OnWindowResize(g_xres, g_yres);
@@ -141,8 +133,6 @@ MESSAGEHANDLER(InitGraphics)
 
 MESSAGEHANDLER(Shutdown)
 {
-	UNUSED2(msg);
-
 	// Empty the CommandProc, to get rid of its references to entities before
 	// we kill the EntityManager
 	GetCommandProc().Destroy();
@@ -159,7 +149,6 @@ MESSAGEHANDLER(Shutdown)
 
 QUERYHANDLER(Exit)
 {
-	UNUSED2(msg);
 	g_AtlasGameLoop->running = false;
 }
 

source/tools/atlas/GameInterface/Handlers/MessageHandler.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2009 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -36,7 +36,7 @@ extern msgHandlers& GetMsgHandlers();
 		ENSURE(msg->GetType() == IMessage::expectedtype); \
 		f##t (static_cast<prefix##t*>(msg)); \
 	} \
-	void f##t(prefix##t* msg)
+	void f##t([[maybe_unused]] prefix##t* msg)
 
 #define MESSAGEHANDLER(t) THINGHANDLER(m, Message, t)
 #define QUERYHANDLER(t) THINGHANDLER(q, Query, t)

source/tools/atlas/GameInterface/Handlers/MiscHandlers.cpp

@@ -1,4 +1,4 @@
-/* Copyright (C) 2022 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -55,13 +55,10 @@ MESSAGEHANDLER(Screenshot)
 
 QUERYHANDLER(Ping)
 {
-	UNUSED2(msg);
 }
 
 MESSAGEHANDLER(SimStopMusic)
 {
-	UNUSED2(msg);
-
 	CmpPtr<ICmpSoundManager> cmpSoundManager(*g_Game->GetSimulation2(), SYSTEM_ENTITY);
 	if (cmpSoundManager)
 		cmpSoundManager->StopMusic();

source/tools/atlas/GameInterface/Handlers/ObjectHandlers.cpp

@@ -412,8 +412,6 @@ QUERYHANDLER(GetCurrentSelection)
 
 MESSAGEHANDLER(ObjectPreviewToEntity)
 {
-	UNUSED2(msg);
-
 	if (g_PreviewEntitiesID.size() == 0)
 		return;
 
@@ -713,8 +711,6 @@ QUERYHANDLER(PickSimilarObjects)
 
 MESSAGEHANDLER(ResetSelectionColor)
 {
-	UNUSED2(msg);
-
 	for (entity_id_t ent : g_Selection)
 	{
 		CmpPtr<ICmpVisual> cmpVisual(*g_Game->GetSimulation2(), ent);