Re: [ANN] Lua 5.2.0 (rc2) now available

[Patrick Donnelly <batrick@...>]

On Mon, Nov 28, 2011 at 12:51 PM, Roberto Ierusalimschy
<roberto@inf.puc-rio.br> wrote:
>> Roberto Ierusalimschy <roberto@inf.puc-rio.br> wrote:
>> >
>> > 277c277
>> > <   exit(status);
>> > ---
>> > >   return (exit(status), 0);
>>
>> That's an error because exit() doesn't return a value :-)
>>
>> I think in this case the compiler is wrong to produce the warning. Good
>> implementations have an annotation on exit() to say it never returns.
>> This is not a bug in Lua.
>
> The problem here is that this kind of annotation is not ANSI. So, some
> compilers have the annotation and rightfully complain when there is a
> return, and some do not have the annotation and rightfully (for their
> knowledge) complain when there is no return.
>
> Would this trick satisfy all compilers?
>
> diff -r1.35 loslib.c
> 277c277,278
> <   exit(status);
> ---
>>   if (L) exit(status);  /* test to avoid warnings of 'exit' x 'return' */
>>   return 0;

I think this would be foolproof:

lua_pushnumber(L, 0);
if (lua_isnumber(L, -1)) exit(status);
return 0;

-- 
- Patrick Donnelly