Re: C++ exceptions

On Thu, Jul 05, 2007 at 02:54:33AM +0100, Pedro Alves wrote:
> #define TRY_EXCEPTION_HANDLER                   \
>     struct eh_data __ehd;                       \
>     int __ret = setjmp(__ehd.env);              \
>     if (!__ret) {                               \
>         start_ehandling(&__ehd);
> 
> #define CATCH_EXCEPTION_HANDLER                 \
>         end_ehandling(&__ehd);                  \
>     } else
> 
> Very nice.  Hiding the __ehd would be great.  If not possible
> then I suggest at least adding ##__LINE__ to it.

I suppose one could do something like:

#define TRY_SEH                                 \
    do {                                        \
        struct eh_data __ehd;                   \
        int __ret = setjmp(__ehd.env);          \
        if (!__ret) {                           \
            start_ehandling(&__ehd);

#define CATCH_SEH                               \
            end_ehandling(&__ehd);              \
        } else {

#define END_SEH                                 \
        }                                       \
    } while (0);

which would be used with:

  TRY_SEH
  {
    while (wcount--)
      *vaddr++ = value;
  }
  CATCH_SEH
  {
    Output(C_ERROR "EXCEPTION while writing %08x to address %p",
      value, vaddr);
  }
  END_SEH

This has the advantage that it should work with C code.  (I'm pretty
sure you could hide __ehd and not require an END decl with C++, but it
would look ugly and not be significantly better than the previous
implementation.)

Earlier on, I tried to use the same __try/__except syntax that msdn
documents.  However, I gave up on it - it was too complicated and not
useful for me.  In particular, implementing __finally would be
painful.

-Kevin

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