在開發過程中經常遇到這種情況，程式在客戶那裡執行的時候會偶然的出現異常，而在開發環境裡卻很難重現問題導致排查問題非常困難，通過下面的方法可以通過dump檔案將出現異常時的程序dump記下來，事後通過windbg等除錯工具分析問題的詳細過程。

首先在程序的入口處設定捕獲未處理異常，在異常處理回撥裡記錄記憶體dump，完成後退出程序，因為本程序記錄dump會導致dump不準確，我們通過另外一個程序來記錄dump。

獲取到dump檔案後通過windbg開啟，kv顯示呼叫棧，找到我們感興趣的異常資訊，這個函式的引數記錄異常的詳細資訊，通過這個引數就能獲取到異常的詳細資訊。

未處理異常回調：

long __stdcall unhandle_exception_filter( _EXCEPTION_POINTERS *msg)
{
	WriteErrorLogA("unhandle error");
	mstring path;
	GetModuleFileNameA(NULL, path.alloc(MAX_PATH), MAX_PATH);
	PathAppendA(path.alloc(MAX_PATH), "..//error_log");
	path.setbuffer();
	SHCreateDirectoryExA(NULL, path, NULL);
	mstring file;
	SYSTEMTIME time;
	GetSystemTime(&time);

	file.format(
		"%hs\\%04d%02d%02d%02d%02d%02d_%08x.dmp",
		path.c_str(),
		time.wYear,
		time.wMonth,
		time.wDay,
		time.wHour,
		time.wMinute,
		time.wSecond,
		GetTickCount());
	
	mstring tmp;
	GetModuleFileNameA(NULL, tmp.alloc(MAX_PATH), MAX_PATH);
	PathAppendA(tmp.alloc(MAX_PATH), "..\\memlog.exe");
	tmp.setbuffer();
	mstring mem;
	mem.format("%hs %d \"%hs\"", tmp.c_str(), GetCurrentProcessId(), file.c_str());

	//create_mem_log(GetCurrentProcessId(), file.c_str());
	STARTUPINFOA si = { sizeof(si) };   
	PROCESS_INFORMATION pi;   
	si.dwFlags = STARTF_USESHOWWINDOW;   
	si.wShowWindow = TRUE;
	BOOL ret = CreateProcessA(   
		NULL,  
		(char *)(mem.c_str()), 
		NULL,   
		NULL,   
		FALSE,   
		CREATE_NEW_CONSOLE,   
		NULL,   
		NULL,   
		&si,   
		&pi);   
	
	if (!ret)
	{
		WriteErrorLogA("create mem process error\n");
	}
	else
	{
		WaitForSingleObject(pi.hProcess, 5000);
		//Sleep(5000);
	}
	exit(-1);
	return 0;
}
 

設定未處理異常回調：

int WINAPI WinMain(HINSTANCE module, HINSTANCE parent, char * cmd, int show)

{
	SetLastError(0);
	HANDLE mutex = CreateMutexA(NULL, NULL, "global/omserver/mutex");
	if (ERROR_ALREADY_EXISTS == GetLastError())
	{
		MessageBoxA(0, "omserver已經啟動", "error", 0);
		return 0;
	}

	SetUnhandledExceptionFilter(unhandle_exception_filter);
 

}

獨立程序記錄異常資訊：

void create_mem_log(int pid, const char *path)
{
	HANDLE dump = NULL;
	SYSTEMTIME time = {0};
	HANDLE h = NULL;

	do 
	{
		dump = CreateFileA(
			path,
			GENERIC_WRITE,
			0,
			NULL,
			CREATE_ALWAYS,
			FILE_ATTRIBUTE_NORMAL,
			NULL);

		if (!dump || INVALID_HANDLE_VALUE == dump)
		{
			WriteErrorLogA("create dump file error\n");
			break;
		}

		MINIDUMP_EXCEPTION_INFORMATION mini_dump_info;
		mini_dump_info.ExceptionPointers = NULL;
		mini_dump_info.ThreadId = GetCurrentThreadId();
		mini_dump_info.ClientPointers = TRUE;
		h = OpenProcess(PROCESS_ALL_ACCESS, FALSE, pid);

		if (!h || INVALID_HANDLE_VALUE == h)
		{
			WriteErrorLogA("open process error\n"); 
			break;
		}

		if (!MiniDumpWriteDump(
			h,
			pid,
			dump,
			MiniDumpNormal,
			NULL,
			NULL,
			NULL))
		{
			WriteErrorLogA("write dump file error, error = %d\n", GetLastError());
			break;
		}
	} while (FALSE);

	if (dump && INVALID_HANDLE_VALUE != dump)
	{
		CloseHandle(dump);
	}

	if (h && INVALID_HANDLE_VALUE != h)
	{
		CloseHandle(h);
	}
	return; 
}