fix: fix fatal error of ExceptionHelper in x86 environemnt.

- fix a wrong placeholder of printf in ExceptionHelper which cause crash in unhandled exception handler.
- improve format function in ExceptionHelper.
- add a new debugging option and macro in CMake script and code for the convenience of debugging unhandled exception handler.
- add docuementation about previous term.

CMakeLists.txt

@@ -7,6 +7,7 @@ project(YYCC
 # Provide options
 option(YYCC_BUILD_TESTBENCH "Build testbench of YYCCommonplace." OFF)
 option(YYCC_BUILD_DOC "Build document of YYCCommonplace." OFF)
+option(YYCC_DEBUG_UE_FILTER "YYCC developer used switch for testing Windows unhandled exception filter. Should not set to ON!!!" OFF)
 
 # Setup install path from CMake provided install path for convenient use.
 include(GNUInstallDirs)

doc/src/intro.dox

@@ -159,4 +159,11 @@ that MSVC distribution places all static library under one director \c lib.
 Thus in MSVC project user can simply spcify the install path of YYCC,
 and use MSVC macros in path to choose correct static library for linking
 
+\section intro__debug Debug Tips
+
+YYCC CMake build script contains a special option called \c YYCC_DEBUG_UE_FILTER.
+If you set it to true, it will add a public macro \c YYCC_DEBUG_UE_FILTER to YYCC project.
+This macro will enable special code path for the convenience of debugging \ref exception_helper related features.
+So in common use, user should not enable this option.
+
 */

src/CMakeLists.txt

@@ -62,8 +62,11 @@ PROPERTIES
     CXX_STANDARD_REQUIRED 17
     CXX_EXTENSION OFF
 )
-# Order Unicode charset for private using
 target_compile_definitions(YYCCommonplace
+# Debug macro should populate to child projects
+PUBLIC
+    $<$<BOOL:${YYCC_DEBUG_UE_FILTER}>:YYCC_DEBUG_UE_FILTER>
+# Unicode charset for private using
 PRIVATE
     $<$<CXX_COMPILER_ID:MSVC>:UNICODE>
     $<$<CXX_COMPILER_ID:MSVC>:_UNICODE>

src/ExceptionHelper.cpp

@@ -242,33 +242,6 @@ namespace YYCC::ExceptionHelper {
 		}
 	}
 
-	/**
-	 * @brief Error log (including backtrace) used output function with format feature
-	 * @details
-	 * This function will format message first.
-	 * And write them into given file stream and stderr.
-	 * @param[in] fs
-	 * The file stream where we write.
-	 * If it is nullptr, function will skip writing for file stream.
-	 * @param[in] fmt The format string.
-	 * @param[in] ... The argument to be formatted.
-	*/
-	static void UExceptionErrLogFormatLine(std::FILE* fs, const yycc_char8_t* fmt, ...) {
-		// write to file
-		if (fs != nullptr) {
-			va_list arg1;
-			va_start(arg1, fmt);
-			std::vfprintf(fs, EncodingHelper::ToOrdinary(fmt), arg1);
-			std::fputs("\n", fs);
-			va_end(arg1);
-		}
-		// write to stderr
-		va_list arg2;
-		va_start(arg2, fmt);
-		ConsoleHelper::ErrWriteLine(YYCC::StringHelper::VPrintf(fmt, arg2).c_str());
-		va_end(arg2);
-	}
-
 	/**
 	 * @brief Error log (including backtrace) used output function
 	 * @details
@@ -288,6 +261,27 @@ namespace YYCC::ExceptionHelper {
 		ConsoleHelper::ErrWriteLine(strl);
 	}
 
+	/**
+	 * @brief Error log (including backtrace) used output function with format feature
+	 * @details
+	 * This function will format message first.
+	 * And write them into given file stream and stderr.
+	 * @param[in] fs
+	 * The file stream where we write.
+	 * If it is nullptr, function will skip writing for file stream.
+	 * @param[in] fmt The format string.
+	 * @param[in] ... The argument to be formatted.
+	*/
+	static void UExceptionErrLogFormatLine(std::FILE* fs, const yycc_char8_t* fmt, ...) {
+		// do format first
+		va_list arg;
+		va_start(arg, fmt);
+		auto fmt_result = YYCC::StringHelper::VPrintf(fmt, arg);
+		va_end(arg);
+		// write to file and console
+		UExceptionErrLogWriteLine(fs, fmt_result.c_str());
+	}
+
 	static void UExceptionBacktrace(FILE* fs, LPCONTEXT context, int maxdepth) {
 		// setup loading symbol options
 		SymSetOptions(SymGetOptions() | SYMOPT_DEFERRED_LOADS | SYMOPT_LOAD_LINES);	// lazy load symbol, and load line number.
@@ -356,12 +350,12 @@ namespace YYCC::ExceptionHelper {
 			}
 
 			// get module name
-			const yycc_char8_t* module_name = YYCC_U8("<unknown module>");
-			yycc_u8string module_name_raw;
+			const yycc_char8_t* no_module_name = YYCC_U8("<unknown module>");
+			yycc_u8string module_name(no_module_name);
 			DWORD64 module_base;
 			if (module_base = SymGetModuleBase64(process, frame.AddrPC.Offset)) {
-				if (WinFctHelper::GetModuleFileName((HINSTANCE)module_base, module_name_raw)) {
-					module_name = module_name_raw.c_str();
+				if (!WinFctHelper::GetModuleFileName((HINSTANCE)module_base, module_name)) {
+					module_name = no_module_name;
 				}
 			}
 
@@ -377,9 +371,12 @@ namespace YYCC::ExceptionHelper {
 			}
 
 			// write to file
-			UExceptionErrLogFormatLine(fs, YYCC_U8("0x%" PRI_XPTR_LEFT_PADDING PRIXPTR "[%s+0x%" PRI_XPTR_LEFT_PADDING PRIXPTR "]\t%s#L%" PRIu64),
+			// MARK: should not use PRIXPTR to print adddress.
+			// because Windows always use DWORD64 as the type of address.
+			// use PRIX64 instead.
+			UExceptionErrLogFormatLine(fs, YYCC_U8("0x%" PRI_XPTR_LEFT_PADDING PRIX64 "[%s+0x%" PRI_XPTR_LEFT_PADDING PRIX64 "]\t%s#L%" PRIu64),
 				frame.AddrPC.Offset, // memory adress
-				module_name, frame.AddrPC.Offset - module_base, // module name + relative address
+				module_name.c_str(), frame.AddrPC.Offset - module_base, // module name + relative address
 				source_file, source_file_line // source file + source line
 			);
 
@@ -555,6 +552,12 @@ namespace YYCC::ExceptionHelper {
 		g_ExceptionRegister.Unregister();
 	}
 
+#if defined(YYCC_DEBUG_UE_FILTER)
+	long __stdcall DebugCallUExceptionImpl(void* data) {
+		return UExceptionImpl(static_cast<LPEXCEPTION_POINTERS>(data));
+	}
+#endif
+
 }
 
 #endif

src/ExceptionHelper.hpp

@@ -55,6 +55,10 @@ namespace YYCC::ExceptionHelper {
 	*/
 	void Unregister();
 
+#if defined(YYCC_DEBUG_UE_FILTER)
+	long __stdcall DebugCallUExceptionImpl(void*);
+#endif
+
 }
 
 #endif

testbench/main.cpp

@@ -349,8 +349,20 @@ namespace YYCCTestbench {
 		});
 
 		// Perform a div zero exception.
+#if defined (YYCC_DEBUG_UE_FILTER)
+		// Reference: https://stackoverflow.com/questions/20981982/is-it-possible-to-debug-unhandledexceptionfilters-with-a-debugger
+		__try {
+			// all of code normally inside of main or WinMain here...
+			int i = 1, j = 0;
+			int k = i / j;
+		}
+		__except (YYCC::ExceptionHelper::DebugCallUExceptionImpl(GetExceptionInformation())) {
+			OutputDebugStringW(L"executed filter function\n");
+		}
+#else
 		int i = 1, j = 0;
 		int k = i / j;
+#endif
 
 		YYCC::ExceptionHelper::Unregister();