(ARTICLE) Attaching a debugger at startup

(ARTICLE) Attaching a debugger at startup

Sometimes you need to debug a process, and you need to attach the debugger right away, but you cannot launch the process under the debugger. For example, if the process you need to debug is a Windows Service, the Windows Service Manager must launch the process. How can you debug it?

Here are the two easiest solutions:

Windows includes registry settings under the ‘Image File Execution Options’ key that can help you debug this. (http://blogs.msdn.com/greggm/archive/2005/02/21/377663.aspx). Most of the information is that blog is still correct. A few updates worth mentioning though: Visual Studio 2008 can support session 0 processes on Vista or Server 2008. Visual Studio 2008 can support 64-bit operating systems. The only remaining 64-bit restriction is that 64-bit managed processes cannot be debugged this way since the .NET Framework does not support managed+native debugging of 64-bit processes. Visual Studio 2005 does not support this feature on Windows Vista or Server 2008. You will need to upgrade to 2008 for these operating systems.

You can add code to your app to cause it to pause waiting for a debugger to attach. I am attaching an example header file for making this work. We ship several executables that embed similar code for this reason. Just call ‘RuntimeDiagnostics::CheckPauseOnStartupOption()’ as the first line of code in your main routine. You can do something verify similar for managed code as well.

Just call ‘System.Diagnostics.Debugger.IsAttached’ instead of IsDebuggerPresent. int _tmain(int argc, _TCHAR* argv[]) { RuntimeDiagnostics::CheckPauseOnStartupOption(); return 0; } Then set this registy key if you need your app to pause: Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\sample.exe] "PauseOnStartup"=dword:00000001

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courtesy: blogs.msdn.com