Codechange: Use null pointer literal instead of the NULL macro

9 files changed, 130 insertions, 130 deletions

diff --git a/src/os/macosx/crashlog_osx.cpp b/src/os/macosx/crashlog_osx.cpp
index c1b321340..16c029639 100644
--- a/src/os/macosx/crashlog_osx.cpp
+++ b/src/os/macosx/crashlog_osx.cpp
@@ -66,7 +66,7 @@ class CrashLogOSX : public CrashLog {
 				" Machine:  %s\n"
 				" Min Ver:  %d\n",
 				ver_maj, ver_min, ver_bug,
-				arch != NULL ? arch->description : "unknown",
+				arch != nullptr ? arch->description : "unknown",
 				MAC_OS_X_VERSION_MIN_REQUIRED
 		);
 	}
@@ -79,7 +79,7 @@ class CrashLogOSX : public CrashLog {
 				" Message: %s\n\n",
 				strsignal(this->signum),
 				this->signum,
-				message == NULL ? "<none>" : message
+				message == nullptr ? "<none>" : message
 		);
 	}
 
@@ -99,14 +99,14 @@ class CrashLogOSX : public CrashLog {
 		frame = (void **)__builtin_frame_address(0);
 #endif
 
-		for (int i = 0; frame != NULL && i < MAX_STACK_FRAMES; i++) {
+		for (int i = 0; frame != nullptr && i < MAX_STACK_FRAMES; i++) {
 			/* Get IP for current stack frame. */
 #if defined(__ppc__) || defined(__ppc64__)
 			void *ip = frame[2];
 #else
 			void *ip = frame[1];
 #endif
-			if (ip == NULL) break;
+			if (ip == nullptr) break;
 
 			/* Print running index. */
 			buffer += seprintf(buffer, last, " [%02d]", i);
@@ -118,7 +118,7 @@ class CrashLogOSX : public CrashLog {
 			if (dl_valid && dli.dli_fname) {
 				/* Valid image name? Extract filename from the complete path. */
 				const char *s = strrchr(dli.dli_fname, '/');
-				if (s != NULL) {
+				if (s != nullptr) {
 					fname = s + 1;
 				} else {
 					fname = dli.dli_fname;
@@ -128,13 +128,13 @@ class CrashLogOSX : public CrashLog {
 			buffer += seprintf(buffer, last, " %-20s " PRINTF_PTR, fname, (uintptr_t)ip);
 
 			/* Print function offset if information is available. */
-			if (dl_valid && dli.dli_sname != NULL && dli.dli_saddr != NULL) {
+			if (dl_valid && dli.dli_sname != nullptr && dli.dli_saddr != nullptr) {
 				/* Try to demangle a possible C++ symbol. */
 				int status = -1;
-				char *func_name = abi::__cxa_demangle(dli.dli_sname, NULL, 0, &status);
+				char *func_name = abi::__cxa_demangle(dli.dli_sname, nullptr, 0, &status);
 
 				long int offset = (intptr_t)ip - (intptr_t)dli.dli_saddr;
-				buffer += seprintf(buffer, last, " (%s + %ld)", func_name != NULL ? func_name : dli.dli_sname, offset);
+				buffer += seprintf(buffer, last, " (%s + %ld)", func_name != nullptr ? func_name : dli.dli_sname, offset);
 
 				free(func_name);
 			}
diff --git a/src/os/macosx/splash.cpp b/src/os/macosx/splash.cpp
index eadb78510..1ddb165b3 100644
--- a/src/os/macosx/splash.cpp
+++ b/src/os/macosx/splash.cpp
@@ -54,7 +54,7 @@ static void PNGAPI png_my_warning(png_structp png_ptr, png_const_charp message)
 void DisplaySplashImage()
 {
 	FILE *f = FioFOpenFile(SPLASH_IMAGE_FILE, "r", BASESET_DIR);
-	if (f == NULL) return;
+	if (f == nullptr) return;
 
 	png_byte header[8];
 	fread(header, sizeof(png_byte), 8, f);
@@ -63,23 +63,23 @@ void DisplaySplashImage()
 		return;
 	}
 
-	png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp) NULL, png_my_error, png_my_warning);
+	png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp) nullptr, png_my_error, png_my_warning);
 
-	if (png_ptr == NULL) {
+	if (png_ptr == nullptr) {
 		fclose(f);
 		return;
 	}
 
 	png_infop info_ptr = png_create_info_struct(png_ptr);
-	if (info_ptr == NULL) {
-		png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
+	if (info_ptr == nullptr) {
+		png_destroy_read_struct(&png_ptr, (png_infopp)nullptr, (png_infopp)nullptr);
 		fclose(f);
 		return;
 	}
 
 	png_infop end_info = png_create_info_struct(png_ptr);
-	if (end_info == NULL) {
-		png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
+	if (end_info == nullptr) {
+		png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)nullptr);
 		fclose(f);
 		return;
 	}
@@ -93,7 +93,7 @@ void DisplaySplashImage()
 	png_init_io(png_ptr, f);
 	png_set_sig_bytes(png_ptr, 8);
 
-	png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
+	png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, nullptr);
 
 	uint width      = png_get_image_width(png_ptr, info_ptr);
 	uint height     = png_get_image_height(png_ptr, info_ptr);
diff --git a/src/os/macosx/string_osx.cpp b/src/os/macosx/string_osx.cpp
index 580be3520..6d90b91a8 100644
--- a/src/os/macosx/string_osx.cpp
+++ b/src/os/macosx/string_osx.cpp
@@ -22,7 +22,7 @@
 
 #if (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5)
 /** Cached current locale. */
-static CFLocaleRef _osx_locale = NULL;
+static CFLocaleRef _osx_locale = nullptr;
 /** CoreText cache for font information, cleared when OTTD changes fonts. */
 static CTFontRef _font_cache[FS_END];
 
@@ -125,21 +125,21 @@ static CGFloat SpriteFontGetWidth(void *ref_con)
 }
 
 static CTRunDelegateCallbacks _sprite_font_callback = {
-	kCTRunDelegateCurrentVersion, NULL, NULL, NULL,
+	kCTRunDelegateCurrentVersion, nullptr, nullptr, nullptr,
 	&SpriteFontGetWidth
 };
 
 /* static */ ParagraphLayouter *CoreTextParagraphLayoutFactory::GetParagraphLayout(CharType *buff, CharType *buff_end, FontMap &fontMapping)
 {
-	if (!MacOSVersionIsAtLeast(10, 5, 0)) return NULL;
+	if (!MacOSVersionIsAtLeast(10, 5, 0)) return nullptr;
 
 	/* Can't layout an empty string. */
 	ptrdiff_t length = buff_end - buff;
-	if (length == 0) return NULL;
+	if (length == 0) return nullptr;
 
 	/* Can't layout our in-built sprite fonts. */
 	for (const auto &i : fontMapping) {
-		if (i.second->fc->IsBuiltInFont()) return NULL;
+		if (i.second->fc->IsBuiltInFont()) return nullptr;
 	}
 
 	/* Make attributed string with embedded font information. */
@@ -156,10 +156,10 @@ static CTRunDelegateCallbacks _sprite_font_callback = {
 	for (const auto &i : fontMapping) {
 		if (i.first - last == 0) continue;
 
-		if (_font_cache[i.second->fc->GetSize()] == NULL) {
+		if (_font_cache[i.second->fc->GetSize()] == nullptr) {
 			/* Cache font information. */
 			CFStringRef font_name = CFStringCreateWithCString(kCFAllocatorDefault, i.second->fc->GetFontName(), kCFStringEncodingUTF8);
-			_font_cache[i.second->fc->GetSize()] = CTFontCreateWithName(font_name, i.second->fc->GetFontSize(), NULL);
+			_font_cache[i.second->fc->GetSize()] = CTFontCreateWithName(font_name, i.second->fc->GetFontSize(), nullptr);
 			CFRelease(font_name);
 		}
 		CFAttributedStringSetAttribute(str, CFRangeMake(last, i.first - last), kCTFontAttributeName, _font_cache[i.second->fc->GetSize()]);
@@ -185,12 +185,12 @@ static CTRunDelegateCallbacks _sprite_font_callback = {
 	CTTypesetterRef typesetter = CTTypesetterCreateWithAttributedString(str);
 	CFRelease(str);
 
-	return typesetter != NULL ? new CoreTextParagraphLayout(typesetter, buff, length, fontMapping) : NULL;
+	return typesetter != nullptr ? new CoreTextParagraphLayout(typesetter, buff, length, fontMapping) : nullptr;
 }
 
 /* virtual */ std::unique_ptr<const ParagraphLayouter::Line> CoreTextParagraphLayout::NextLine(int max_width)
 {
-	if (this->cur_offset >= this->length) return NULL;
+	if (this->cur_offset >= this->length) return nullptr;
 
 	/* Get line break position, trying word breaking first and breaking somewhere if that doesn't work. */
 	CFIndex len = CTTypesetterSuggestLineBreak(this->typesetter, this->cur_offset, max_width);
@@ -200,7 +200,7 @@ static CTRunDelegateCallbacks _sprite_font_callback = {
 	CTLineRef line = CTTypesetterCreateLine(this->typesetter, CFRangeMake(this->cur_offset, len));
 	this->cur_offset += len;
 
-	return std::unique_ptr<const Line>(line != NULL ? new CoreTextLine(line, this->font_map, this->text_buffer) : NULL);
+	return std::unique_ptr<const Line>(line != nullptr ? new CoreTextLine(line, this->font_map, this->text_buffer) : nullptr);
 }
 
 CoreTextParagraphLayout::CoreTextVisualRun::CoreTextVisualRun(CTRunRef run, Font *font, const CoreTextParagraphLayoutFactory::CharType *buff) : font(font)
@@ -233,7 +233,7 @@ CoreTextParagraphLayout::CoreTextVisualRun::CoreTextVisualRun(CTRunRef run, Font
 			this->positions[i * 2 + 1] = pts[i].y;
 		}
 	}
-	this->total_advance = (int)CTRunGetTypographicBounds(run, CFRangeMake(0, 0), NULL, NULL, NULL);
+	this->total_advance = (int)CTRunGetTypographicBounds(run, CFRangeMake(0, 0), nullptr, nullptr, nullptr);
 	this->positions[this->glyphs.size() * 2] = this->positions[0] + this->total_advance;
 }
 
@@ -271,9 +271,9 @@ int CoreTextParagraphLayout::CoreTextLine::GetWidth() const
 /** Delete CoreText font reference for a specific font size. */
 void MacOSResetScriptCache(FontSize size)
 {
-	if (_font_cache[size] != NULL) {
+	if (_font_cache[size] != nullptr) {
 		CFRelease(_font_cache[size]);
-		_font_cache[size] = NULL;
+		_font_cache[size] = nullptr;
 	}
 }
 
@@ -282,7 +282,7 @@ void MacOSSetCurrentLocaleName(const char *iso_code)
 {
 	if (!MacOSVersionIsAtLeast(10, 5, 0)) return;
 
-	if (_osx_locale != NULL) CFRelease(_osx_locale);
+	if (_osx_locale != nullptr) CFRelease(_osx_locale);
 
 	CFStringRef iso = CFStringCreateWithCString(kCFAllocatorNull, iso_code, kCFStringEncodingUTF8);
 	_osx_locale = CFLocaleCreate(kCFAllocatorDefault, iso);
@@ -425,7 +425,7 @@ int MacOSStringCompare(const char *s1, const char *s2)
 
 /* static */ StringIterator *OSXStringIterator::Create()
 {
-	if (!MacOSVersionIsAtLeast(10, 5, 0)) return NULL;
+	if (!MacOSVersionIsAtLeast(10, 5, 0)) return nullptr;
 
 	return new OSXStringIterator();
 }
@@ -441,11 +441,11 @@ int MacOSStringCompare(const char *s1, const char *s2)
 
 /* static */ StringIterator *OSXStringIterator::Create()
 {
-	return NULL;
+	return nullptr;
 }
 
 /* static */ ParagraphLayouter *CoreTextParagraphLayoutFactory::GetParagraphLayout(CharType *buff, CharType *buff_end, FontMap &fontMapping)
 {
-	return NULL;
+	return nullptr;
 }
 #endif /* (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5) */
diff --git a/src/os/os2/os2.cpp b/src/os/os2/os2.cpp
index 70c75a410..9ba6f8ef9 100644
--- a/src/os/os2/os2.cpp
+++ b/src/os/os2/os2.cpp
@@ -102,7 +102,7 @@ bool FiosGetDiskFreeSpace(const char *path, uint64 *tot)
 	struct diskfree_t free;
 	char drive = path[0] - 'A' + 1;
 
-	if (tot != NULL && _getdiskfree(drive, &free) == 0) {
+	if (tot != nullptr && _getdiskfree(drive, &free) == 0) {
 		*tot = free.avail_clusters * free.sectors_per_cluster * free.bytes_per_sector;
 		return true;
 	}
@@ -119,7 +119,7 @@ bool FiosGetDiskFreeSpace(const char *path, uint64 *tot)
 		free = (uint64)s.f_frsize * s.f_bavail;
 	}
 #endif
-	if (tot != NULL) *tot = free;
+	if (tot != nullptr) *tot = free;
 	return true;
 #endif
 }
@@ -173,7 +173,7 @@ void ShowOSErrorBox(const char *buf, bool system)
 
 int CDECL main(int argc, char *argv[])
 {
-	SetRandomSeed(time(NULL));
+	SetRandomSeed(time(nullptr));
 
 	/* Make sure our arguments contain only valid UTF-8 characters. */
 	for (int i = 0; i < argc; i++) ValidateString(argv[i]);
@@ -191,7 +191,7 @@ bool GetClipboardContents(char *buffer, const char *last)
 	{
 		const char *text = (const char*)WinQueryClipbrdData(hab, CF_TEXT);
 
-		if (text != NULL)
+		if (text != nullptr)
 		{
 			strecpy(buffer, text, last);
 			WinCloseClipbrd(hab);
diff --git a/src/os/unix/crashlog_unix.cpp b/src/os/unix/crashlog_unix.cpp
index 2e9f4215f..005babebd 100644
--- a/src/os/unix/crashlog_unix.cpp
+++ b/src/os/unix/crashlog_unix.cpp
@@ -68,7 +68,7 @@ class CrashLogUnix : public CrashLog {
 				" Message: %s\n\n",
 				strsignal(this->signum),
 				this->signum,
-				message == NULL ? "<none>" : message
+				message == nullptr ? "<none>" : message
 		);
 	}
 
diff --git a/src/os/unix/unix.cpp b/src/os/unix/unix.cpp
index aa63019f6..430e3770f 100644
--- a/src/os/unix/unix.cpp
+++ b/src/os/unix/unix.cpp
@@ -84,7 +84,7 @@ bool FiosGetDiskFreeSpace(const char *path, uint64 *tot)
 	if (statvfs(path, &s) != 0) return false;
 	free = (uint64)s.f_frsize * s.f_bavail;
 #endif
-	if (tot != NULL) *tot = free;
+	if (tot != nullptr) *tot = free;
 	return true;
 }
 
@@ -130,9 +130,9 @@ static const char *GetLocalCode()
 #else
 	/* Strip locale (eg en_US.UTF-8) to only have UTF-8 */
 	const char *locale = GetCurrentLocale("LC_CTYPE");
-	if (locale != NULL) locale = strchr(locale, '.');
+	if (locale != nullptr) locale = strchr(locale, '.');
 
-	return (locale == NULL) ? "" : locale + 1;
+	return (locale == nullptr) ? "" : locale + 1;
 #endif
 }
 
@@ -158,7 +158,7 @@ static const char *convert_tofrom_fs(iconv_t convd, const char *name)
 
 	strecpy(outbuf, name, outbuf + outlen);
 
-	iconv(convd, NULL, NULL, NULL, NULL);
+	iconv(convd, nullptr, nullptr, nullptr, nullptr);
 	if (iconv(convd, &inbuf, &inlen, &outbuf, &outlen) == (size_t)(-1)) {
 		DEBUG(misc, 0, "[iconv] error converting '%s'. Errno %d", name, errno);
 	}
@@ -246,13 +246,13 @@ int CDECL main(int argc, char *argv[])
 	cocoaSetupAutoreleasePool();
 	/* This is passed if we are launched by double-clicking */
 	if (argc >= 2 && strncmp(argv[1], "-psn", 4) == 0) {
-		argv[1] = NULL;
+		argv[1] = nullptr;
 		argc = 1;
 	}
 #endif
 	CrashLog::InitialiseCrashLog();
 
-	SetRandomSeed(time(NULL));
+	SetRandomSeed(time(nullptr));
 
 	signal(SIGPIPE, SIG_IGN);
 
@@ -282,7 +282,7 @@ void OSOpenBrowser(const char *url)
 	const char *args[3];
 	args[0] = "xdg-open";
 	args[1] = url;
-	args[2] = NULL;
+	args[2] = nullptr;
 	execvp(args[0], const_cast<char * const *>(args));
 	DEBUG(misc, 0, "Failed to open url: %s", url);
 	exit(0);
diff --git a/src/os/windows/crashlog_win.cpp b/src/os/windows/crashlog_win.cpp
index 458a76163..a19789976 100644
--- a/src/os/windows/crashlog_win.cpp
+++ b/src/os/windows/crashlog_win.cpp
@@ -66,7 +66,7 @@ public:
 	 * A crash log is always generated when it's generated.
 	 * @param ep the data related to the exception.
 	 */
-	CrashLogWindows(EXCEPTION_POINTERS *ep = NULL) :
+	CrashLogWindows(EXCEPTION_POINTERS *ep = nullptr) :
 		ep(ep)
 	{
 		this->crashlog[0] = '\0';
@@ -81,7 +81,7 @@ public:
 	static CrashLogWindows *current;
 };
 
-/* static */ CrashLogWindows *CrashLogWindows::current = NULL;
+/* static */ CrashLogWindows *CrashLogWindows::current = nullptr;
 
 /* virtual */ char *CrashLogWindows::LogOSVersion(char *buffer, const char *last) const
 {
@@ -114,7 +114,7 @@ public:
 			" Message:   %s\n\n",
 			(int)ep->ExceptionRecord->ExceptionCode,
 			(size_t)ep->ExceptionRecord->ExceptionAddress,
-			message == NULL ? "<none>" : message
+			message == nullptr ? "<none>" : message
 	);
 }
 
@@ -156,7 +156,7 @@ static void GetFileInfo(DebugFileInfo *dfi, const TCHAR *filename)
 	HANDLE file;
 	memset(dfi, 0, sizeof(*dfi));
 
-	file = CreateFile(filename, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, 0);
+	file = CreateFile(filename, GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING, 0, 0);
 	if (file != INVALID_HANDLE_VALUE) {
 		byte buffer[1024];
 		DWORD numread;
@@ -165,7 +165,7 @@ static void GetFileInfo(DebugFileInfo *dfi, const TCHAR *filename)
 		uint32 crc = (uint32)-1;
 
 		for (;;) {
-			if (ReadFile(file, buffer, sizeof(buffer), &numread, NULL) == 0 || numread == 0) {
+			if (ReadFile(file, buffer, sizeof(buffer), &numread, nullptr) == 0 || numread == 0) {
 				break;
 			}
 			filesize += numread;
@@ -174,7 +174,7 @@ static void GetFileInfo(DebugFileInfo *dfi, const TCHAR *filename)
 		dfi->size = filesize;
 		dfi->crc32 = crc ^ (uint32)-1;
 
-		if (GetFileTime(file, NULL, NULL, &write_time)) {
+		if (GetFileTime(file, nullptr, nullptr, &write_time)) {
 			FileTimeToSystemTime(&write_time, &dfi->file_time);
 		}
 		CloseHandle(file);
@@ -217,7 +217,7 @@ static char *PrintModuleInfo(char *output, const char *last, HMODULE mod)
 		BOOL res;
 
 		HANDLE proc = OpenProcess(PROCESS_ALL_ACCESS, FALSE, GetCurrentProcessId());
-		if (proc != NULL) {
+		if (proc != nullptr) {
 			res = EnumProcessModules(proc, modules, sizeof(modules), &needed);
 			CloseHandle(proc);
 			if (res) {
@@ -228,7 +228,7 @@ static char *PrintModuleInfo(char *output, const char *last, HMODULE mod)
 			}
 		}
 	}
-	output = PrintModuleInfo(output, last, NULL);
+	output = PrintModuleInfo(output, last, nullptr);
 	return output + seprintf(output, last, "\n");
 }
 
@@ -362,7 +362,7 @@ char *CrashLogWindows::AppendDecodedStacktrace(char *buffer, const char *last) c
 	if (LoadLibraryList((Function*)&proc, dbg_import)) {
 		/* Initialize symbol handler. */
 		HANDLE hCur = GetCurrentProcess();
-		proc.pSymInitialize(hCur, NULL, TRUE);
+		proc.pSymInitialize(hCur, nullptr, TRUE);
 		/* Load symbols only when needed, fail silently on errors, demangle symbol names. */
 		proc.pSymSetOptions(SYMOPT_DEFERRED_LOADS | SYMOPT_FAIL_CRITICAL_ERRORS | SYMOPT_UNDNAME);
 
@@ -399,7 +399,7 @@ char *CrashLogWindows::AppendDecodedStacktrace(char *buffer, const char *last) c
 #else
 				IMAGE_FILE_MACHINE_I386,
 #endif
-				hCur, GetCurrentThread(), &frame, &ctx, NULL, proc.pSymFunctionTableAccess64, proc.pSymGetModuleBase64, NULL)) break;
+				hCur, GetCurrentThread(), &frame, &ctx, nullptr, proc.pSymFunctionTableAccess64, proc.pSymGetModuleBase64, nullptr)) break;
 
 			if (frame.AddrPC.Offset == frame.AddrReturn.Offset) {
 				buffer += seprintf(buffer, last, " <infinite loop>\n");
@@ -443,16 +443,16 @@ char *CrashLogWindows::AppendDecodedStacktrace(char *buffer, const char *last) c
 {
 	int ret = 0;
 	HMODULE dbghelp = LoadLibrary(_T("dbghelp.dll"));
-	if (dbghelp != NULL) {
+	if (dbghelp != nullptr) {
 		typedef BOOL (WINAPI *MiniDumpWriteDump_t)(HANDLE, DWORD, HANDLE,
 				MINIDUMP_TYPE,
 				CONST PMINIDUMP_EXCEPTION_INFORMATION,
 				CONST PMINIDUMP_USER_STREAM_INFORMATION,
 				CONST PMINIDUMP_CALLBACK_INFORMATION);
 		MiniDumpWriteDump_t funcMiniDumpWriteDump = (MiniDumpWriteDump_t)GetProcAddress(dbghelp, "MiniDumpWriteDump");
-		if (funcMiniDumpWriteDump != NULL) {
+		if (funcMiniDumpWriteDump != nullptr) {
 			seprintf(filename, filename_last, "%scrash.dmp", _personal_dir);
-			HANDLE file  = CreateFile(OTTD2FS(filename), GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, 0, 0);
+			HANDLE file  = CreateFile(OTTD2FS(filename), GENERIC_WRITE, 0, nullptr, CREATE_ALWAYS, 0, 0);
 			HANDLE proc  = GetCurrentProcess();
 			DWORD procid = GetCurrentProcessId();
 			MINIDUMP_EXCEPTION_INFORMATION mdei;
@@ -470,7 +470,7 @@ char *CrashLogWindows::AppendDecodedStacktrace(char *buffer, const char *last) c
 			mdei.ExceptionPointers  = ep;
 			mdei.ClientPointers     = false;
 
-			funcMiniDumpWriteDump(proc, procid, file, MiniDumpWithDataSegs, &mdei, &musi, NULL);
+			funcMiniDumpWriteDump(proc, procid, file, MiniDumpWithDataSegs, &mdei, &musi, nullptr);
 			ret = 1;
 		} else {
 			ret = -1;
@@ -488,11 +488,11 @@ static void ShowCrashlogWindow();
  * Stack pointer for use when 'starting' the crash handler.
  * Not static as gcc's inline assembly needs it that way.
  */
-void *_safe_esp = NULL;
+void *_safe_esp = nullptr;
 
 static LONG WINAPI ExceptionHandler(EXCEPTION_POINTERS *ep)
 {
-	if (CrashLogWindows::current != NULL) {
+	if (CrashLogWindows::current != nullptr) {
 		CrashLog::AfterCrashLogCleanup();
 		ExitProcess(2);
 	}
@@ -501,7 +501,7 @@ static LONG WINAPI ExceptionHandler(EXCEPTION_POINTERS *ep)
 		static const TCHAR _emergency_crash[] =
 			_T("A serious fault condition occurred in the game. The game will shut down.\n")
 			_T("As you loaded an emergency savegame no crash information will be generated.\n");
-		MessageBox(NULL, _emergency_crash, _T("Fatal Application Failure"), MB_ICONERROR);
+		MessageBox(nullptr, _emergency_crash, _T("Fatal Application Failure"), MB_ICONERROR);
 		ExitProcess(3);
 	}
 
@@ -510,7 +510,7 @@ static LONG WINAPI ExceptionHandler(EXCEPTION_POINTERS *ep)
 			_T("A serious fault condition occurred in the game. The game will shut down.\n")
 			_T("As you loaded an savegame for which you do not have the required NewGRFs\n")
 			_T("no crash information will be generated.\n");
-		MessageBox(NULL, _saveload_crash, _T("Fatal Application Failure"), MB_ICONERROR);
+		MessageBox(nullptr, _saveload_crash, _T("Fatal Application Failure"), MB_ICONERROR);
 		ExitProcess(3);
 	}
 
@@ -525,7 +525,7 @@ static LONG WINAPI ExceptionHandler(EXCEPTION_POINTERS *ep)
 	/* Close any possible log files */
 	CloseConsoleLogIfActive();
 
-	if ((VideoDriver::GetInstance() == NULL || VideoDriver::GetInstance()->HasGUI()) && _safe_esp != NULL) {
+	if ((VideoDriver::GetInstance() == nullptr || VideoDriver::GetInstance()->HasGUI()) && _safe_esp != nullptr) {
 #ifdef _M_AMD64
 		ep->ContextRecord->Rip = (DWORD64)ShowCrashlogWindow;
 		ep->ContextRecord->Rsp = (DWORD64)_safe_esp;
@@ -542,7 +542,7 @@ static LONG WINAPI ExceptionHandler(EXCEPTION_POINTERS *ep)
 
 static void CDECL CustomAbort(int signal)
 {
-	RaiseException(0xE1212012, 0, 0, NULL);
+	RaiseException(0xE1212012, 0, 0, nullptr);
 }
 
 /* static */ void CrashLog::InitialiseCrashLog()
@@ -693,5 +693,5 @@ static void ShowCrashlogWindow()
 {
 	ShowCursor(TRUE);
 	ShowWindow(GetActiveWindow(), FALSE);
-	DialogBox(GetModuleHandle(NULL), MAKEINTRESOURCE(100), NULL, CrashDialogFunc);
+	DialogBox(GetModuleHandle(nullptr), MAKEINTRESOURCE(100), nullptr, CrashDialogFunc);
 }
diff --git a/src/os/windows/string_uniscribe.cpp b/src/os/windows/string_uniscribe.cpp
index 5abe848bd..8c4e11d3f 100644
--- a/src/os/windows/string_uniscribe.cpp
+++ b/src/os/windows/string_uniscribe.cpp
@@ -86,7 +86,7 @@ public:
 		int num_glyphs;
 		Font *font;
 
-		mutable int *glyph_to_char = NULL;
+		mutable int *glyph_to_char = nullptr;
 
 	public:
 		UniscribeVisualRun(const UniscribeRun &range, int x);
@@ -139,9 +139,9 @@ public:
 
 void UniscribeResetScriptCache(FontSize size)
 {
-	if (_script_cache[size] != NULL) {
+	if (_script_cache[size] != nullptr) {
 		ScriptFreeCache(&_script_cache[size]);
-		_script_cache[size] = NULL;
+		_script_cache[size] = nullptr;
 	}
 }
 
@@ -168,9 +168,9 @@ static bool UniscribeShapeRun(const UniscribeParagraphLayoutFactory::CharType *b
 	/* The char-to-glyph array is the same size as the input. */
 	range.char_to_glyph.resize(range.len);
 
-	HDC temp_dc = NULL;
-	HFONT old_font = NULL;
-	HFONT cur_font = NULL;
+	HDC temp_dc = nullptr;
+	HFONT old_font = nullptr;
+	HFONT cur_font = nullptr;
 
 	while (true) {
 		/* Shape the text run by determining the glyphs needed for display. */
@@ -217,9 +217,9 @@ static bool UniscribeShapeRun(const UniscribeParagraphLayoutFactory::CharType *b
 		} else if (hr == E_PENDING) {
 			/* Glyph data is not in cache, load native font. */
 			cur_font = HFontFromFont(range.font);
-			if (cur_font == NULL) return false; // Sorry, no dice.
+			if (cur_font == nullptr) return false; // Sorry, no dice.
 
-			temp_dc = CreateCompatibleDC(NULL);
+			temp_dc = CreateCompatibleDC(nullptr);
 			SetMapMode(temp_dc, MM_TEXT);
 			old_font = (HFONT)SelectObject(temp_dc, cur_font);
 		} else if (hr == USP_E_SCRIPT_NOT_IN_FONT && range.sa.eScript != SCRIPT_UNDEFINED) {
@@ -227,19 +227,19 @@ static bool UniscribeShapeRun(const UniscribeParagraphLayoutFactory::CharType *b
 			range.sa.eScript = SCRIPT_UNDEFINED;
 		} else {
 			/* Some unknown other error. */
-			if (temp_dc != NULL) {
+			if (temp_dc != nullptr) {
 				SelectObject(temp_dc, old_font);
 				DeleteObject(cur_font);
-				ReleaseDC(NULL, temp_dc);
+				ReleaseDC(nullptr, temp_dc);
 			}
 			return false;
 		}
 	}
 
-	if (temp_dc != NULL) {
+	if (temp_dc != nullptr) {
 		SelectObject(temp_dc, old_font);
 		DeleteObject(cur_font);
-		ReleaseDC(NULL, temp_dc);
+		ReleaseDC(nullptr, temp_dc);
 	}
 
 	return true;
@@ -280,16 +280,16 @@ static std::vector<SCRIPT_ITEM> UniscribeItemizeString(UniscribeParagraphLayoutF
 {
 	int32 length = buff_end - buff;
 	/* Can't layout an empty string. */
-	if (length == 0) return NULL;
+	if (length == 0) return nullptr;
 
 	/* Can't layout our in-built sprite fonts. */
 	for (auto const &pair : fontMapping) {
-		if (pair.second->fc->IsBuiltInFont()) return NULL;
+		if (pair.second->fc->IsBuiltInFont()) return nullptr;
 	}
 
 	/* Itemize text. */
 	std::vector<SCRIPT_ITEM> items = UniscribeItemizeString(buff, length);
-	if (items.size() == 0) return NULL;
+	if (items.size() == 0) return nullptr;
 
 	/* Build ranges from the items and the font map. A range is a run of text
 	 * that is part of a single item and formatted using a single font style. */
@@ -306,7 +306,7 @@ static std::vector<SCRIPT_ITEM> UniscribeItemizeString(UniscribeParagraphLayoutF
 
 			/* Shape the range. */
 			if (!UniscribeShapeRun(buff, ranges.back())) {
-				return NULL;
+				return nullptr;
 			}
 
 			/* If we are at the end of the current item, advance to the next item. */
@@ -323,7 +323,7 @@ static std::vector<SCRIPT_ITEM> UniscribeItemizeString(UniscribeParagraphLayoutF
 	std::vector<UniscribeRun>::iterator start_run = this->cur_range;
 	std::vector<UniscribeRun>::iterator last_run = this->cur_range;
 
-	if (start_run == this->ranges.end()) return NULL;
+	if (start_run == this->ranges.end()) return nullptr;
 
 	/* Add remaining width of the first run if it is a broken run. */
 	int cur_width = 0;
@@ -355,7 +355,7 @@ static std::vector<SCRIPT_ITEM> UniscribeItemizeString(UniscribeParagraphLayoutF
 		int last_cluster = this->cur_range_offset + 1;
 		for (std::vector<UniscribeRun>::iterator r = start_run; r != last_run; r++) {
 			log_attribs.resize(r->pos - start_run->pos + r->len);
-			if (FAILED(ScriptBreak(this->text_buffer + r->pos + start_offs, r->len - start_offs, &r->sa, &log_attribs[r->pos - start_run->pos + start_offs]))) return NULL;
+			if (FAILED(ScriptBreak(this->text_buffer + r->pos + start_offs, r->len - start_offs, &r->sa, &log_attribs[r->pos - start_run->pos + start_offs]))) return nullptr;
 
 			std::vector<int> dx(r->len);
 			ScriptGetLogicalWidths(&r->sa, r->len, (int)r->glyphs.size(), &r->advances[0], &r->char_to_glyph[0], &r->vis_attribs[0], &dx[0]);
@@ -401,7 +401,7 @@ static std::vector<SCRIPT_ITEM> UniscribeItemizeString(UniscribeParagraphLayoutF
 		bidi_level.push_back(r->sa.s.uBidiLevel);
 	}
 	std::vector<INT> vis_to_log(bidi_level.size());
-	if (FAILED(ScriptLayout((int)bidi_level.size(), &bidi_level[0], &vis_to_log[0], NULL))) return NULL;
+	if (FAILED(ScriptLayout((int)bidi_level.size(), &bidi_level[0], &vis_to_log[0], nullptr))) return nullptr;
 
 	/* Create line. */
 	std::unique_ptr<UniscribeLine> line(new UniscribeLine());
@@ -415,14 +415,14 @@ static std::vector<SCRIPT_ITEM> UniscribeItemizeString(UniscribeParagraphLayoutF
 		if (i_run == last_run - 1 && remaing_offset < (last_run - 1)->len) {
 			run.len = remaing_offset - 1;
 
-			if (!UniscribeShapeRun(this->text_buffer, run)) return NULL;
+			if (!UniscribeShapeRun(this->text_buffer, run)) return nullptr;
 		}
 		if (i_run == start_run && this->cur_range_offset > 0) {
 			assert(run.len - this->cur_range_offset > 0);
 			run.pos += this->cur_range_offset;
 			run.len -= this->cur_range_offset;
 
-			if (!UniscribeShapeRun(this->text_buffer, run)) return NULL;
+			if (!UniscribeShapeRun(this->text_buffer, run)) return nullptr;
 		}
 
 		line->emplace_back(run, cur_pos);
@@ -490,12 +490,12 @@ UniscribeParagraphLayout::UniscribeVisualRun::UniscribeVisualRun(UniscribeVisual
 								  start_pos(other.start_pos), total_advance(other.total_advance), num_glyphs(other.num_glyphs), font(other.font)
 {
 	this->glyph_to_char = other.glyph_to_char;
-	other.glyph_to_char = NULL;
+	other.glyph_to_char = nullptr;
 }
 
 const int *UniscribeParagraphLayout::UniscribeVisualRun::GetGlyphToCharMap() const
 {
-	if (this->glyph_to_char == NULL) {
+	if (this->glyph_to_char == nullptr) {
 		this->glyph_to_char = CallocT<int>(this->GetGlyphCount());
 
 		/* The char to glyph array contains the first glyph index of the cluster that is associated
diff --git a/src/os/windows/win32.cpp b/src/os/windows/win32.cpp
index ae78407ac..b0495d64d 100644
--- a/src/os/windows/win32.cpp
+++ b/src/os/windows/win32.cpp
@@ -61,14 +61,14 @@ bool LoadLibraryList(Function proc[], const char *dll)
 		HMODULE lib;
 		lib = LoadLibrary(MB_TO_WIDE(dll));
 
-		if (lib == NULL) return false;
+		if (lib == nullptr) return false;
 		for (;;) {
 			FARPROC p;
 
 			while (*dll++ != '\0') { /* Nothing */ }
 			if (*dll == '\0') break;
 			p = GetProcAddress(lib, dll);
-			if (p == NULL) return false;
+			if (p == nullptr) return false;
 			*proc++ = (Function)p;
 		}
 		dll++;
@@ -84,7 +84,7 @@ void ShowOSErrorBox(const char *buf, bool system)
 
 void OSOpenBrowser(const char *url)
 {
-	ShellExecute(GetActiveWindow(), _T("open"), OTTD2FS(url), NULL, NULL, SW_SHOWNORMAL);
+	ShellExecute(GetActiveWindow(), _T("open"), OTTD2FS(url), nullptr, nullptr, SW_SHOWNORMAL);
 }
 
 /* Code below for windows version of opendir/readdir/closedir copied and
@@ -142,7 +142,7 @@ DIR *opendir(const TCHAR *path)
 
 	if ((fa != INVALID_FILE_ATTRIBUTES) && (fa & FILE_ATTRIBUTE_DIRECTORY)) {
 		d = dir_calloc();
-		if (d != NULL) {
+		if (d != nullptr) {
 			TCHAR search_path[MAX_PATH];
 			bool slash = path[_tcslen(path) - 1] == '\\';
 
@@ -158,14 +158,14 @@ DIR *opendir(const TCHAR *path)
 				d->at_first_entry = true;
 			} else {
 				dir_free(d);
-				d = NULL;
+				d = nullptr;
 			}
 		} else {
 			errno = ENOMEM;
 		}
 	} else {
 		/* path not found or not a directory */
-		d = NULL;
+		d = nullptr;
 		errno = ENOENT;
 	}
 
@@ -179,11 +179,11 @@ struct dirent *readdir(DIR *d)
 
 	if (d->at_first_entry) {
 		/* the directory was empty when opened */
-		if (d->hFind == INVALID_HANDLE_VALUE) return NULL;
+		if (d->hFind == INVALID_HANDLE_VALUE) return nullptr;
 		d->at_first_entry = false;
 	} else if (!FindNextFile(d->hFind, &d->fd)) { // determine cause and bail
 		if (GetLastError() == ERROR_NO_MORE_FILES) SetLastError(prev_err);
-		return NULL;
+		return nullptr;
 	}
 
 	/* This entry has passed all checks; return information about it.
@@ -251,7 +251,7 @@ bool FiosGetDiskFreeSpace(const char *path, uint64 *tot)
 	DWORD spc, bps, nfc, tnc;
 
 	_sntprintf(root, lengthof(root), _T("%c:") _T(PATHSEP), path[0]);
-	if (tot != NULL && GetDiskFreeSpace(root, &spc, &bps, &nfc, &tnc)) {
+	if (tot != nullptr && GetDiskFreeSpace(root, &spc, &bps, &nfc, &tnc)) {
 		*tot = ((spc * bps) * (uint64)nfc);
 		retval = true;
 	}
@@ -339,9 +339,9 @@ void CreateConsole()
 	*stderr = *fdopen(2, "w" );
 #endif
 
-	setvbuf(stdin, NULL, _IONBF, 0);
-	setvbuf(stdout, NULL, _IONBF, 0);
-	setvbuf(stderr, NULL, _IONBF, 0);
+	setvbuf(stdin, nullptr, _IONBF, 0);
+	setvbuf(stdout, nullptr, _IONBF, 0);
+	setvbuf(stderr, nullptr, _IONBF, 0);
 }
 
 /** Temporary pointer to get the help message to the window */
@@ -398,7 +398,7 @@ void ShowInfo(const char *str)
 			 * ShowInfo are much shorter, or so long they need this way of displaying
 			 * them anyway. */
 			_help_msg = str;
-			DialogBox(GetModuleHandle(NULL), MAKEINTRESOURCE(101), NULL, HelpDialogFunc);
+			DialogBox(GetModuleHandle(nullptr), MAKEINTRESOURCE(101), nullptr, HelpDialogFunc);
 		} else {
 			/* We need to put the text in a separate buffer because the default
 			 * buffer in OTTD2FS might not be large enough (512 chars). */
@@ -459,28 +459,28 @@ void DetermineBasePaths(const char *exe)
 	char tmp[MAX_PATH];
 	TCHAR path[MAX_PATH];
 #ifdef WITH_PERSONAL_DIR
-	if (SUCCEEDED(OTTDSHGetFolderPath(NULL, CSIDL_PERSONAL, NULL, SHGFP_TYPE_CURRENT, path))) {
+	if (SUCCEEDED(OTTDSHGetFolderPath(nullptr, CSIDL_PERSONAL, nullptr, SHGFP_TYPE_CURRENT, path))) {
 		strecpy(tmp, FS2OTTD(path), lastof(tmp));
 		AppendPathSeparator(tmp, lastof(tmp));
 		strecat(tmp, PERSONAL_DIR, lastof(tmp));
 		AppendPathSeparator(tmp, lastof(tmp));
 		_searchpaths[SP_PERSONAL_DIR] = stredup(tmp);
 	} else {
-		_searchpaths[SP_PERSONAL_DIR] = NULL;
+		_searchpaths[SP_PERSONAL_DIR] = nullptr;
 	}
 
-	if (SUCCEEDED(OTTDSHGetFolderPath(NULL, CSIDL_COMMON_DOCUMENTS, NULL, SHGFP_TYPE_CURRENT, path))) {
+	if (SUCCEEDED(OTTDSHGetFolderPath(nullptr, CSIDL_COMMON_DOCUMENTS, nullptr, SHGFP_TYPE_CURRENT, path))) {
 		strecpy(tmp, FS2OTTD(path), lastof(tmp));
 		AppendPathSeparator(tmp, lastof(tmp));
 		strecat(tmp, PERSONAL_DIR, lastof(tmp));
 		AppendPathSeparator(tmp, lastof(tmp));
 		_searchpaths[SP_SHARED_DIR] = stredup(tmp);
 	} else {
-		_searchpaths[SP_SHARED_DIR] = NULL;
+		_searchpaths[SP_SHARED_DIR] = nullptr;
 	}
 #else
-	_searchpaths[SP_PERSONAL_DIR] = NULL;
-	_searchpaths[SP_SHARED_DIR]   = NULL;
+	_searchpaths[SP_PERSONAL_DIR] = nullptr;
+	_searchpaths[SP_SHARED_DIR]   = nullptr;
 #endif
 
 	/* Get the path to working directory of OpenTTD */
@@ -488,15 +488,15 @@ void DetermineBasePaths(const char *exe)
 	AppendPathSeparator(tmp, lastof(tmp));
 	_searchpaths[SP_WORKING_DIR] = stredup(tmp);
 
-	if (!GetModuleFileName(NULL, path, lengthof(path))) {
+	if (!GetModuleFileName(nullptr, path, lengthof(path))) {
 		DEBUG(misc, 0, "GetModuleFileName failed (%lu)\n", GetLastError());
-		_searchpaths[SP_BINARY_DIR] = NULL;
+		_searchpaths[SP_BINARY_DIR] = nullptr;
 	} else {
 		TCHAR exec_dir[MAX_PATH];
 		_tcsncpy(path, convert_to_fs(exe, path, lengthof(path)), lengthof(path));
-		if (!GetFullPathName(path, lengthof(exec_dir), exec_dir, NULL)) {
+		if (!GetFullPathName(path, lengthof(exec_dir), exec_dir, nullptr)) {
 			DEBUG(misc, 0, "GetFullPathName failed (%lu)\n", GetLastError());
-			_searchpaths[SP_BINARY_DIR] = NULL;
+			_searchpaths[SP_BINARY_DIR] = nullptr;
 		} else {
 			strecpy(tmp, convert_from_fs(exec_dir, tmp, lengthof(tmp)), lastof(tmp));
 			char *s = strrchr(tmp, PATHSEPCHAR);
@@ -505,8 +505,8 @@ void DetermineBasePaths(const char *exe)
 		}
 	}
 
-	_searchpaths[SP_INSTALLATION_DIR]       = NULL;
-	_searchpaths[SP_APPLICATION_BUNDLE_DIR] = NULL;
+	_searchpaths[SP_INSTALLATION_DIR]       = nullptr;
+	_searchpaths[SP_APPLICATION_BUNDLE_DIR] = nullptr;
 }
 
 
@@ -516,18 +516,18 @@ bool GetClipboardContents(char *buffer, const char *last)
 	const char *ptr;
 
 	if (IsClipboardFormatAvailable(CF_UNICODETEXT)) {
-		OpenClipboard(NULL);
+		OpenClipboard(nullptr);
 		cbuf = GetClipboardData(CF_UNICODETEXT);
 
 		ptr = (const char*)GlobalLock(cbuf);
-		int out_len = WideCharToMultiByte(CP_UTF8, 0, (LPCWSTR)ptr, -1, buffer, (last - buffer) + 1, NULL, NULL);
+		int out_len = WideCharToMultiByte(CP_UTF8, 0, (LPCWSTR)ptr, -1, buffer, (last - buffer) + 1, nullptr, nullptr);
 		GlobalUnlock(cbuf);
 		CloseClipboard();
 
 		if (out_len == 0) return false;
 #if !defined(UNICODE)
 	} else if (IsClipboardFormatAvailable(CF_TEXT)) {
-		OpenClipboard(NULL);
+		OpenClipboard(nullptr);
 		cbuf = GetClipboardData(CF_TEXT);
 
 		ptr = (const char*)GlobalLock(cbuf);
@@ -596,7 +596,7 @@ char *convert_from_fs(const TCHAR *name, char *utf8_buf, size_t buflen)
 	const WCHAR *wide_buf = name;
 #else
 	/* Convert string from the local codepage to UTF-16. */
-	int wide_len = MultiByteToWideChar(CP_ACP, 0, name, -1, NULL, 0);
+	int wide_len = MultiByteToWideChar(CP_ACP, 0, name, -1, nullptr, 0);
 	if (wide_len == 0) {
 		utf8_buf[0] = '\0';
 		return utf8_buf;
@@ -607,7 +607,7 @@ char *convert_from_fs(const TCHAR *name, char *utf8_buf, size_t buflen)
 #endif
 
 	/* Convert UTF-16 string to UTF-8. */
-	int len = WideCharToMultiByte(CP_UTF8, 0, wide_buf, -1, utf8_buf, (int)buflen, NULL, NULL);
+	int len = WideCharToMultiByte(CP_UTF8, 0, wide_buf, -1, utf8_buf, (int)buflen, nullptr, nullptr);
 	if (len == 0) utf8_buf[0] = '\0';
 
 	return utf8_buf;
@@ -630,7 +630,7 @@ TCHAR *convert_to_fs(const char *name, TCHAR *system_buf, size_t buflen, bool co
 	int len = MultiByteToWideChar(CP_UTF8, 0, name, -1, system_buf, (int)buflen);
 	if (len == 0) system_buf[0] = '\0';
 #else
-	int len = MultiByteToWideChar(CP_UTF8, 0, name, -1, NULL, 0);
+	int len = MultiByteToWideChar(CP_UTF8, 0, name, -1, nullptr, 0);
 	if (len == 0) {
 		system_buf[0] = '\0';
 		return system_buf;
@@ -639,7 +639,7 @@ TCHAR *convert_to_fs(const char *name, TCHAR *system_buf, size_t buflen, bool co
 	WCHAR *wide_buf = AllocaM(WCHAR, len);
 	MultiByteToWideChar(CP_UTF8, 0, name, -1, wide_buf, len);
 
-	len = WideCharToMultiByte(console_cp ? CP_OEMCP : CP_ACP, 0, wide_buf, len, system_buf, (int)buflen, NULL, NULL);
+	len = WideCharToMultiByte(console_cp ? CP_OEMCP : CP_ACP, 0, wide_buf, len, system_buf, (int)buflen, nullptr, nullptr);
 	if (len == 0) system_buf[0] = '\0';
 #endif
 
@@ -654,7 +654,7 @@ TCHAR *convert_to_fs(const char *name, TCHAR *system_buf, size_t buflen, bool co
  */
 HRESULT OTTDSHGetFolderPath(HWND hwnd, int csidl, HANDLE hToken, DWORD dwFlags, LPTSTR pszPath)
 {
-	static HRESULT (WINAPI *SHGetFolderPath)(HWND, int, HANDLE, DWORD, LPTSTR) = NULL;
+	static HRESULT (WINAPI *SHGetFolderPath)(HWND, int, HANDLE, DWORD, LPTSTR) = nullptr;
 	static bool first_time = true;
 
 	/* We only try to load the library one time; if it fails, it fails */
@@ -674,7 +674,7 @@ HRESULT OTTDSHGetFolderPath(HWND hwnd, int csidl, HANDLE hToken, DWORD dwFlags,
 		first_time = false;
 	}
 
-	if (SHGetFolderPath != NULL) return SHGetFolderPath(hwnd, csidl, hToken, dwFlags, pszPath);
+	if (SHGetFolderPath != nullptr) return SHGetFolderPath(hwnd, csidl, hToken, dwFlags, pszPath);
 
 	/* SHGetFolderPath doesn't exist, try a more conservative approach,
 	 * eg environment variables. This is only included for legacy modes
@@ -698,7 +698,7 @@ HRESULT OTTDSHGetFolderPath(HWND hwnd, int csidl, HANDLE hToken, DWORD dwFlags,
 				HKEY key;
 				if (RegOpenKeyEx(csidl == CSIDL_PERSONAL ? HKEY_CURRENT_USER : HKEY_LOCAL_MACHINE, REGSTR_PATH_SPECIAL_FOLDERS, 0, KEY_READ, &key) != ERROR_SUCCESS) break;
 				DWORD len = MAX_PATH;
-				ret = RegQueryValueEx(key, csidl == CSIDL_PERSONAL ? _T("Personal") : _T("Common Documents"), NULL, NULL, (LPBYTE)pszPath, &len);
+				ret = RegQueryValueEx(key, csidl == CSIDL_PERSONAL ? _T("Personal") : _T("Common Documents"), nullptr, nullptr, (LPBYTE)pszPath, &len);
 				RegCloseKey(key);
 				if (ret == ERROR_SUCCESS) return (HRESULT)0;
 				break;
@@ -718,7 +718,7 @@ const char *GetCurrentLocale(const char *)
 	if (GetLocaleInfoA(LOCALE_USER_DEFAULT, LOCALE_SISO639LANGNAME, lang, lengthof(lang)) == 0 ||
 	    GetLocaleInfoA(LOCALE_USER_DEFAULT, LOCALE_SISO3166CTRYNAME, country, lengthof(country)) == 0) {
 		/* Unable to retrieve the locale. */
-		return NULL;
+		return nullptr;
 	}
 	/* Format it as 'en_us'. */
 	static char retbuf[6] = {lang[0], lang[1], '_', country[0], country[1], 0};
@@ -750,7 +750,7 @@ void Win32SetCurrentLocaleName(const char *iso_code)
 int OTTDStringCompare(const char *s1, const char *s2)
 {
 	typedef int (WINAPI *PFNCOMPARESTRINGEX)(LPCWSTR, DWORD, LPCWCH, int, LPCWCH, int, LPVOID, LPVOID, LPARAM);
-	static PFNCOMPARESTRINGEX _CompareStringEx = NULL;
+	static PFNCOMPARESTRINGEX _CompareStringEx = nullptr;
 	static bool first_time = true;
 
 #ifndef SORT_DIGITSASNUMBERS
@@ -765,10 +765,10 @@ int OTTDStringCompare(const char *s1, const char *s2)
 		first_time = false;
 	}
 
-	if (_CompareStringEx != NULL) {
+	if (_CompareStringEx != nullptr) {
 		/* CompareStringEx takes UTF-16 strings, even in ANSI-builds. */
-		int len_s1 = MultiByteToWideChar(CP_UTF8, 0, s1, -1, NULL, 0);
-		int len_s2 = MultiByteToWideChar(CP_UTF8, 0, s2, -1, NULL, 0);
+		int len_s1 = MultiByteToWideChar(CP_UTF8, 0, s1, -1, nullptr, 0);
+		int len_s2 = MultiByteToWideChar(CP_UTF8, 0, s2, -1, nullptr, 0);
 
 		if (len_s1 != 0 && len_s2 != 0) {
 			LPWSTR str_s1 = AllocaM(WCHAR, len_s1);
@@ -777,7 +777,7 @@ int OTTDStringCompare(const char *s1, const char *s2)
 			MultiByteToWideChar(CP_UTF8, 0, s1, -1, str_s1, len_s1);
 			MultiByteToWideChar(CP_UTF8, 0, s2, -1, str_s2, len_s2);
 
-			int result = _CompareStringEx(_cur_iso_locale, LINGUISTIC_IGNORECASE | SORT_DIGITSASNUMBERS, str_s1, -1, str_s2, -1, NULL, NULL, 0);
+			int result = _CompareStringEx(_cur_iso_locale, LINGUISTIC_IGNORECASE | SORT_DIGITSASNUMBERS, str_s1, -1, str_s2, -1, nullptr, nullptr, 0);
 			if (result != 0) return result;
 		}
 	}