SYSREVEAL

Structured Exception Handling (SEH) is a very important mechanism in Windows operating system. The most famous article describing SEH in Windows 32 bits is from Windows wizard Matt Pietrek: A Crash Course on the Depths of Win32™ Structured Exception Handling .

On the x64, Microsoft changes its way to handle exception. You could still use __try and __except to catch and handle exceptions, but the internal implements are totally changed by Microsoft. There are still some good articles talking about the x64 SEH:

A good article for major concepts:  Exceptional Behavior – x64 Structured Exception Handling

Series of articles in depth:  Programming against the x64 exception handling support

So why should we learn these details if we could still use __try and __except to handle all exceptions? The answer is: when you port your code from 32-bit to 64-bit, your SEH might not work if your code is dynamically generated. You have to use new Win64 APIs RtlInstallFunctionTableCallback and RtlAddFunctionTable to manually handle your code exceptions. Furthermore, some PE packers might not work when processing Win64 PE files since they could not take advantage of Win32 SEH tricks any more.