Debugging Delphi ISAPI Dll on Apache

Question

I have run into a situtation where frequently when debugging a ISAPI Dll (TWebModule) running under Apache I get errors. The caption on the error box is "Debugger Fault Notification" and contained in the message is, among other things: "c:\program files\Apache\bin\httpd.exe faulted with message......."

When this happens the cpu window pops up, and I have to hit the "OK" button on the error message. I might have to do this 3 - 5 times before program flow continues.

This is happening on my laptop. I have a desktop with the same exact configuration (as far as I know) and I don't have this problem. Both operating systems are XP. So obviously there is some setting or outdated file somewhere.

Also, I have noticed if first run my website when Apache is not in the debugging envrironment it seems not to have this problem. (i.e. start apache in the services, run my web app, stop the service, and then debug it within the Delphi environment).

Any ideas???

Answer 1

While it doesn't directly answer the how to debug using Apache, another alternate debugging technique which works well is to use idDebugger (near the bottom of that page). It will allow you to debug ISAPI DLL's directly from the IDE without having to start/stop services. I now never develop ISAPI DLL's without it.

Answer 2

To avoid this and other problems, I've started xxm. It's an alternative to TWebModule, and uses a separate wrapper to run with IIS, but there's also an Apache, FireFox and IE wrapper! It also uses mixed-HTML-Delphi-source and the development-mode wrappers do the parsing and an auto-compile to give a web-script-like environment.

Also the InternetExplorer plugin works great in the debugger (with iexplore.exe as host application).

Answer 3

Error code 0xC0000008 is Status_Invalid_Handle. That can be thrown by CloseHandle, for example, when you try to close a handle that either was never open or was already closed. The error might not occur when you're running outside the debugger because the API won't throw an exception unless it's being debugged.

If you're getting that exception in code that the debugger doesn't have access to, then the debugger will display the CPU window instead. Look at the call stack to find the place in your code closest to where the exception came from.

It's also possible that it's not occurring in your code at all. Try doing your same debug routine without your module installed. Do you still get errors?