What's better to use, a __try/__except block or a try / catch block?

Question

I'm wondering which is the better way to catch exceptions that I throw: is it a __try / __except block or a try / catch block?

I'm writing in C++ and the program will only be used on Windows, so portability is not an issue.

Thanks!

Answer 1

They are two very different things. try/catch are the familiar C++ keywords you know. __try/__except is used to catch SEH exceptions. Exceptions raised by Windows itself, like DivisionByZero or AccessViolation. It is well described in the MSDN Library article for it.

You can also use it to catch C++ exception because it leverages the Windows SEH feature. You however can't get the thrown exception object out of it so there will be zero context if you actually want the handle the exception. Which is madness. The number one approach is to not ever catch SEH exceptions, they are always gross. If you do need to marry the two then use _set_se_translator() to convert the SEH exception to a C++ exception.

Answer 2

You should use a try/catch block.

As others have already answered, __try / __except is for catching SEH (windows generated errors) not for catching general exceptions.

Most importantly, __try and __catch may not run C++ destructors or correctly unwind the stack when an exception is thrown.

Except in rare cases, you should never try to catch SEH exceptions.

EDIT: Well, I was positive on this (it's what I've always been told), but @Hans says that apparently there is a compiler switch you can use to change this. I think the docs on /EHa are misleading, or at least incomplete, on what happens here. If someone finds definitive docs which prove this wrong, I'll happily remove this answer.

Even if it turns out this is false, you should still use try and catch simply because they are standard, while __try and __except are not.