What happens if an extern(Windows) function throws?

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:

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;
}

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;
> }

Reply to Sergey,

> What happens if an extern(Windows) function throws?
> 
> 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:
> 
> 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;
> }

you can burry two of those in a function and get

> extern(Windows) export HRESULT DllRegisterServer()
> {
> try
> {
> doStuff();
> }
> catch(Exception e) { return OhCrud(e); }
> catch{ return OhCrud(); }
> return S_OK;
> }