Switch C++ language standard to C++20

docs/source/commandline/commandline-all.rst

@@ -3022,7 +3022,7 @@ Core Sound Options
     * - ``wasapi``
       - Windows
       - Yes
-      - Yes [#SoundWASAPIMonitoring]_
+      - Yes
       - Yes
       - Yes
     * - ``xaudio2``
@@ -3065,9 +3065,6 @@ Core Sound Options
 
 ..  rubric:: Footnotes
 
-..  [#SoundWASAPIMonitoring] MAME requires Windows 10 1703 or later to use
-    output monitoring with WASAPI.
-
 ..  [#SoundXAudio2OS] MAME requires Windows 8 or later to use XAudio2.
 
 ..  [#SoundWinSDL] While SDL is not a supported option on official MAME builds

docs/source/initialsetup/compilingmame.rst

@@ -8,9 +8,9 @@ Compiling MAME
 All Platforms
 -------------
 
-* To compile MAME, you need a C++17 compiler and runtime library.  We
-  support building with GCC version 10.3 or later and clang version 11
-  or later.  MAME should run with GNU libstdc++ version 10.3 or later or
+* To compile MAME, you need a C++20 compiler and runtime library.  We
+  support building with GCC version 11 or later and clang version 11 or
+  later.  MAME should run with GNU libstdc++ version 11 or later or
   libc++ version 11 or later.  The initial release of any major version
   of GCC should be avoided.  For example, if you want to compile MAME
   with GCC 12, you should use version 12.1 or later.
@@ -795,23 +795,6 @@ omitted).
 Issues affecting Microsoft Visual Studio
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Microsoft introduced a new version of XAudio2 with Windows 8 that’s incompatible
-with the version included with DirectX for prior Windows versions at the API
-level.  Newer versions of the Microsoft Windows SDK include headers and libraries
-for the new version of XAudio2.  By default, the target Windows version is set to
-Windows Vista (6.0) when compiling MAME, which prevents the use of this version
-of the XAudio2 headers and libraries.  To build MAME with XAudio2 support using
-the Microsoft Windows SDK, you must do one of the following:
-
-* Add ``MODERN_WIN_API=1`` to the options passed to make when generating the
-  Visual Studio project files.  This will set the target Windows version to
-  Windows 8 (6.2).  The resulting binaries may not run on earlier versions of
-  Windows.
-* Install the `DirectX SDK <https://www.microsoft.com/en-US/download/details.aspx?id=6812>`_ (already included since Windows 8.0 SDK and
-  automatically installed with Visual Studio 2013 and later).  Configure the
-  **osd_windows** project to search the DirectX header/library paths before
-  searching the Microsoft Windows SDK paths.
-
 The MSVC compiler produces spurious warnings about potentially uninitialised
 local variables.  You currently need to add ``NOWERROR=1`` to the options passed
 to make when generating the Visual Studio project files.  This stops warnings
@@ -873,7 +856,7 @@ Using a GCC/GNU libstdc++ installation in a non-standard location on Linux
 GCC may be built and installed to a custom location, typically by supplying the
 **--prefix=** option to the **configure** command.  This may be useful if you
 want to build MAME on a Linux distribution that still uses a version of GNU
-libstdC++ that predates C++17 support.  To use an alternate GCC installation to,
+libstdc++ that predates C++20 support.  To use an alternate GCC installation to
 build MAME, set the C and C++ compilers to the full paths to the **gcc** and
 **g++** commands, and add the library path to the run-time search path.  If you
 installed GCC in /opt/local/gcc72, you might use a command like this::

scripts/genie.lua

@@ -475,7 +475,6 @@ language "C++"
 
 flags {
 	"StaticRuntime",
-	"Cpp17",
 }
 
 	if not _OPTIONS["NOWERROR"] then
@@ -713,11 +712,11 @@ end
 
 local version = str_to_version(_OPTIONS["gcc_version"])
 	buildoptions_cpp {
-		"-std=c++17",
+		"-std=c++20",
 	}
 
 	buildoptions_objcpp {
-		"-std=c++17",
+		"-std=c++20",
 	}
 -- this speeds it up a bit by piping between the preprocessor/compiler/assembler
 	buildoptions {
@@ -1040,8 +1039,8 @@ end
 				}
 			end
 		else
-			if version < 100300 then
-				print("GCC version 10.3 or later needed")
+			if version < 110000 then
+				print("GCC version 11 or later needed")
 				os.exit(-1)
 			end
 			buildoptions_cpp {
@@ -1108,7 +1107,7 @@ configuration { "asmjs" }
 		"-s USE_SDL_TTF=2",
 	}
 	buildoptions_cpp {
-		"-std=c++17",
+		"-std=c++20",
 		"-s EXCEPTION_CATCHING_ALLOWED=\"['_ZN15running_machine17start_all_devicesEv','_ZN12cli_frontend7executeEiPPc','_ZN8chd_file11open_commonEb','_ZN8chd_file13read_metadataEjjRNSt3__212basic_stringIcNS0_11char_traitsIcEENS0_9allocatorIcEEEE','_ZN8chd_file13read_metadataEjjRNSt3__26vectorIhNS0_9allocatorIhEEEE','_ZNK19netlist_mame_device19base_validity_checkER16validity_checker']\"",
 	}
 	defines {
@@ -1295,6 +1294,7 @@ if _OPTIONS["vs"]==nil then
 
 		buildoptions_cpp {
 			"/Zc:__cplusplus",
+			"/std:c++20",
 		}
 
 		flags {

src/emu/device.h

@@ -243,7 +243,7 @@ class device_type_impl_base
 		: m_creator(&create_device<DeviceClass>)
 		, m_type(typeid(DeviceClass))
 		, m_shortname(Traits::shortname)
-		, m_fullname(Traits::fullname)
+		, m_fullname((char const *)Traits::fullname)
 		, m_source(Traits::source)
 		, m_emulation_flags(DeviceClass::emulation_flags())
 		, m_unemulated_features(DeviceClass::unemulated_features())
@@ -258,7 +258,7 @@ class device_type_impl_base
 		: m_creator(&create_driver<DriverClass>)
 		, m_type(typeid(DriverClass))
 		, m_shortname(Traits::shortname)
-		, m_fullname(Traits::fullname)
+		, m_fullname((char const *)Traits::fullname)
 		, m_source(Traits::source)
 		, m_emulation_flags(DriverClass::emulation_flags() | Flags)
 		, m_unemulated_features(DriverClass::unemulated_features() | Unemulated)
@@ -404,7 +404,7 @@ extern emu::detail::device_registrar const registered_device_types;
 			{ \
 				static inline constexpr char const *const shortname = (ShortName); \
 				static inline constexpr char const *const source = __FILE__; \
-				static constexpr char const fullname[] = (FullName); \
+				static constexpr std::remove_reference_t<decltype((FullName)[0])> const fullname[] = (FullName); \
 			}; \
 			constexpr decltype(Type##_device_traits::fullname) Type##_device_traits::fullname; \
 		} \
@@ -446,7 +446,7 @@ extern emu::detail::device_registrar const registered_device_types;
 			{ \
 				static inline constexpr char const *const shortname = (ShortName); \
 				static inline constexpr char const *const source = __FILE__; \
-				static constexpr char const fullname[] = (FullName); \
+				static constexpr std::remove_reference_t<decltype((FullName)[0])> const fullname[] = (FullName); \
 			}; \
 			constexpr decltype(Type##_device_traits::fullname) Type##_device_traits::fullname; \
 		} \

src/emu/gamedrv.h

@@ -186,8 +186,8 @@ class game_driver
 			{ \
 				static inline constexpr char const *const shortname = #NAME; \
 				static inline constexpr char const *const source = __FILE__; \
-				static inline constexpr char const *manufacturer = (COMPANY); \
-				static constexpr char const fullname[] = (FULLNAME); \
+				static inline constexpr auto const *const manufacturer = (COMPANY); \
+				static constexpr std::remove_reference_t<decltype((FULLNAME)[0])> const fullname[] = (FULLNAME); \
 			}; \
 			constexpr decltype(GAME_TRAITS_NAME(NAME)::fullname) GAME_TRAITS_NAME(NAME)::fullname; \
 		}
@@ -257,7 +257,7 @@ extern game_driver const GAME_NAME(NAME)                                \
 	GAME_DRIVER_TYPE(NAME, CLASS, FLAGS),                               \
 	#PARENT,                                                            \
 	#YEAR,                                                              \
-	GAME_TRAITS_NAME(NAME)::manufacturer,                               \
+	(const char *)GAME_TRAITS_NAME(NAME)::manufacturer,                 \
 	[] (machine_config &config, device_t &owner) { downcast<CLASS &>(owner).MACHINE(config); }, \
 	INPUT_PORTS_NAME(INPUT),                                            \
 	[] (device_t &owner) { downcast<CLASS &>(owner).INIT(); },          \
@@ -329,7 +329,7 @@ extern game_driver const GAME_NAME(NAME)                                \
 	GAME_DRIVER_TYPE(NAME, CLASS, FLAGS),                               \
 	#PARENT,                                                            \
 	#YEAR,                                                              \
-	GAME_TRAITS_NAME(NAME)::manufacturer,                               \
+	(const char *)GAME_TRAITS_NAME(NAME)::manufacturer,                 \
 	[] (machine_config &config, device_t &owner) { downcast<CLASS &>(owner).MACHINE(config); }, \
 	INPUT_PORTS_NAME(INPUT),                                            \
 	[] (device_t &owner) { downcast<CLASS &>(owner).INIT(); },          \
@@ -395,7 +395,7 @@ extern game_driver const GAME_NAME(NAME)                                \
 			GAME_DRIVER_TYPE(NAME, CLASS, FLAGS),                               \
 			#PARENT,                                                            \
 			#YEAR,                                                              \
-			GAME_TRAITS_NAME(NAME)::manufacturer,                               \
+			(const char *)GAME_TRAITS_NAME(NAME)::manufacturer,                 \
 			[] (machine_config &config, device_t &owner) { downcast<CLASS &>(owner).MACHINE(config); }, \
 			INPUT_PORTS_NAME(INPUT),                                            \
 			[] (device_t &owner) { downcast<CLASS &>(owner).INIT(); },          \

src/emu/ioport.h

@@ -1076,6 +1076,12 @@ class ioport_configurer
 	ioport_configurer& set_condition(ioport_condition::condition_t condition, const char *tag, ioport_value mask, ioport_value value);
 	ioport_configurer& onoff_alloc(const char *name, ioport_value defval, ioport_value mask, const char *diplocation);
 
+	// allow UTF-8 strings to be used for names transparently
+	ioport_configurer& field_alloc(ioport_type type, ioport_value defval, ioport_value mask, const char8_t *name) { return field_alloc(type, defval, mask, reinterpret_cast<const char *>(name)); }
+	ioport_configurer& field_set_name(const char8_t *name) { return field_set_name(reinterpret_cast<const char *>(name)); }
+	ioport_configurer& setting_alloc(ioport_value value, const char8_t *name) { return setting_alloc(value, reinterpret_cast<const char *>(name)); }
+	ioport_configurer& onoff_alloc(const char8_t *name, ioport_value defval, ioport_value mask, const char *diplocation) { return onoff_alloc(reinterpret_cast<const char *>(name), defval, mask, diplocation); }
+
 private:
 	// internal state
 	device_t &          m_owner;

src/frontend/mame/ui/videoopt.cpp

@@ -148,17 +148,18 @@ void menu_video_options::populate()
 		item_append(menu_item_type::SEPARATOR);
 	}
 
-	const char *subtext = "";
-
-	// add a rotate item
-	switch (m_target.orientation())
 	{
-	case ROT0:      subtext = "None";       break;
-	case ROT90:     subtext = u8"CW 90°";   break;
-	case ROT180:    subtext = u8"180°";     break;
-	case ROT270:    subtext = u8"CCW 90°";  break;
+		// add a rotate item
+		const auto *subtext = u8"";
+		switch (m_target.orientation())
+		{
+		case ROT0:      subtext = u8"None";     break;
+		case ROT90:     subtext = u8"CW 90°";   break;
+		case ROT180:    subtext = u8"180°";     break;
+		case ROT270:    subtext = u8"CCW 90°";  break;
+		}
+		item_append(_("Rotate"), (char const *)subtext, FLAG_LEFT_ARROW | FLAG_RIGHT_ARROW, reinterpret_cast<void *>(ITEM_ROTATE));
 	}
-	item_append(_("Rotate"), subtext, FLAG_LEFT_ARROW | FLAG_RIGHT_ARROW, reinterpret_cast<void *>(ITEM_ROTATE));
 
 	// cropping
 	bool const canzoom(curview.has_art() && !curview.visible_screens().empty());
@@ -167,6 +168,7 @@ void menu_video_options::populate()
 	if (!m_snapshot)
 	{
 		// uneven stretch
+		const auto *subtext = "";
 		switch (m_target.scale_mode())
 		{
 		case SCALE_FRACTIONAL:

src/lib/util/language.h

@@ -38,6 +38,20 @@ char const *lang_translate(char const *context, char const *message);
 std::string_view lang_translate(char const *context, std::string_view message);
 std::string_view lang_translate(std::string_view context, std::string_view message);
 
+// allow UTF-8 messages to be used as keys transparently
+inline char const *lang_translate(char8_t const *message)
+{ return lang_translate(reinterpret_cast<char const *>(message)); }
+inline std::string_view lang_translate(std::u8string_view message)
+{ return lang_translate(std::string_view(reinterpret_cast<char const *>(message.data()), message.size())); }
+
+// allow UTF-8 messages to be used as keys transparently (with context)
+inline char const *lang_translate(char const *context, char8_t const *message)
+{ return lang_translate(context, reinterpret_cast<char const *>(message)); }
+inline std::string_view lang_translate(char const *context, std::u8string_view message)
+{ return lang_translate(context, std::string_view(reinterpret_cast<char const *>(message.data()), message.size())); }
+inline std::string_view lang_translate(std::string_view context, std::u8string_view message)
+{ return lang_translate(context, std::string_view(reinterpret_cast<char const *>(message.data()), message.size())); }
+
 } // namespace util
 
 #endif // MAME_LIB_UTIL_LANGUAGE_H