D Exceptions

[Steven Schveighoffer]

On Tue, 26 Jan 2010 15:07:50 -0500, Nick Sabalausky <a at a.a> wrote:

> "Daniel Keep" <daniel.keep.lists at gmail.com> wrote in message
> news:hjn49d$2kfe$1 at digitalmars.com...
>>
>>
>> Under linux, SIGSEGV is a signal, and you can't safely throw exceptions
>> from signal handlers, so D just aborts.
>>
>
> Just out of curiosity, is that a limitation that comes from the basic
> concept of signals, or just a detail of how the OS just happens to do
> signals?

I think it's because a signal handler is entered at any point in the call  
stack.  This means that to unwind the stack, you need to unwind possibly C  
functions and (I think) even system calls.  The safest thing to do in a  
signal handler is to set a flag indicating a signal was recieved, and then  
asynchronously process it.

Given that you could be in C or C++ land where exceptions either don't  
exist or are different, you face a very difficult task to unwind the stack  
correctly.

-Steve