User-848649084 posted
You can debug your native module by attaching the debugger to the w3wp process.
1)In Visual Studio, go to Tools > Attach to Process >
(select show processes from all sessions, and all users checkboxes at the bottom of the dialog. Make sure Attach Type is Native, or Managed And Native)
2)Select the W3WP.exe process, and click Attach.
3)Go to Debug > Windows > Modules (the naming coincidence is accidental), and make sure that the symbols for your DLL are loaded. If not, Right Click and do Load Symbols, and manually browse to your symbol file.
Put the breakpoint and debug away.
https://stackoverflow.com/questions/3914638/how-to-attach-debug-iis-native-module-with-vs-2010