How can I switch off exception handling in MSVC? - visual-c++

Question

Does anybody know how to switch off exception handling option in MSVC? I tried to set the option 'Enable C++ exceptions' to 'NO' and I got warning:
warning C4530: C++ exception handler used, but unwind semantics are not enabled. Specify /EHsc.
I would like to switch off the exception handler, too, but I don't know how.
In my application I basically need more speed than stability, therefore I chose switching off the exception handling. I do not have any try/catch blocks, but I do use STL. When I switch the option 'Enable C++ exceptions' to 'NO' is there any way how to get rid of those warnings?

Answer 1

Most likely you're including one or more standard C++ headers that contain try/catch. The most typical case would be <iostream> - you will get this error on a file which consists of a single line that just includes that. Any other stream header will also do, as will locales.
If you look closely at the error message, it should reference two filenames, not one - your file, and the included file with the error. E.g. in my sample case of #include <iostream>, I get this:
except.cpp
C:\Program Files\Microsoft Visual Studio 9.0\VC\INCLUDE\xlocale(342) : warning C4530: C++ exception handler used, but unwind semantics are not enabled. Specify /EHsc

Answer 2

If you really don't want exceptions in the STL that will be linked to your program, define _HAS_EXCEPTIONS=0 in your whole project. Better than compiling your code with /EHsc if you don't plan on adding exception handling.

Answer 3

That warning means that you told the compiler you're not going to use exceptions yet you have a try {} catch() {} block in the code. It informs you that although you have that block, if an exception is thrown no desctructors are going to be executed. Turning exceptions off means exactly that - the compiler doesn't produce code for automatic destruction when the stack is unwound in the event of an exceptions.

Answer 4

In Visual Studio, /EH is found at Configuration Properties ➔ C/C++ ➔ Code Generation ➔ Enable C++ Exceptions.

Answer 5

Switching off exceptions is quite hard, as you're dealing with C++ here. It's really in the same category as switching off NULL pointers - how are you going to handle memory allocation failure, for instance?
That said, /EH specifies which exception handling model you want, and "none" is not an option. You can pick /EHa, /EHs, /EHac and /EHsc - [a]ynchronous with or without support for throwing extern "C" functions.

Answer 6

Do you still have try/catch block(s) in your code?
The first thing to do when you get stuck is look up the error on MSDN and/or Google for it. That usually helps. This is what MSDN says:
When the /EHsc option has not been enabled, an object with automatic storage in the frame, between the function doing the throw and the function catching the throw, will not be destroyed. However, an object with automatic storage created in a try or catch block will be destroyed. [...]

Answer 7

Using MSVC aka CL one can simply use the /kernel switch or not have any /EH switch. Windows C/C++ MSVC builds always have SEH. SEH is inbuilt in Windows.
If #if _HAS_EXCEPTIONS == 0 , MS STL will simply switch to SEH.
Is that standard C++? No it is not. Three keywords will be missing: try, throw and catch. And you need to learn about SEH.
So is that a "good thing"? Well for Windows low level C++, SEH is a good thing.
ps: It is not advisable to use /kernel switch, outside of kernel developments.