Exception safety

[Don]

Sergey Gromov wrote:
> What happens if an extern(Windows) function throws?

Very, very bad things.

> Basically I want my export DLL interface functions to fail gracefully.
> What happens if I don't catch?  Currently my typical export looks like
> this, and it looks a bit verbose:

Yup. It's pretty awful, and you need to remember to do it every time.
I do something like:

void doDllRegisterServer()
{
      doStuff();
}

extern(Windows) export HRESULT DllRegisterServer()
{
    mixin(SafeInvoke("doDllRegisterServer()"));
}

where SafeInvoke creates a string mixin which adds all the catch wrappers.




 >
> 
> extern(Windows) export HRESULT DllRegisterServer()
> {
>   try
>   {
>     doStuff();
>   }
>   catch(Exception e)
>   {
>     myTrace("Shit happens. Reason: " ~ e.msg);
>     return E_UNEXPECTED;
>   }
>   catch(Object obj)
>   {
>     myTrace("Shit happens. Reason: " ~ obj.toString());
>     return E_UNEXPECTED;
>   }
>   catch
>   {
>     myTrace("Shit happens. Reason: unknown");
>     return E_UNEXPECTED;
>   }
>   return S_OK;
> }