Thread overview
[Issue 6423] New: Garbage is returned from `void main()`
Aug 01, 2011
Denis
Aug 27, 2013
Iain Buclaw
August 01, 2011
http://d.puremagic.com/issues/show_bug.cgi?id=6423

           Summary: Garbage is returned from `void main()`
           Product: D
           Version: D1 & D2
          Platform: Other
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: verylonglogin.reg@gmail.com


--- Comment #0 from Denis <verylonglogin.reg@gmail.com> 2011-08-01 05:06:43 PDT ---
No `xor eax,eax` instruction added by dmd v1.069/v2.054 so the program returns garbage:

void f(){}

void main() {
    return f();
}

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hsteoh@quickfur.ath.cx changed:

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--- Comment #1 from hsteoh@quickfur.ath.cx 2013-08-27 08:16:42 PDT ---
Still happens on git HEAD.

I'm guessing perhaps the compiler got confused by returning a void function? I'm not sure code like this should be allowed, as it doesn't really make sense to be able to return void (via a return statement) -- nothing is being returned.

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bearophile_hugs@eml.cc changed:

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--- Comment #2 from bearophile_hugs@eml.cc 2013-08-27 08:20:10 PDT ---
(In reply to comment #1)

> I'm guessing perhaps the compiler got confused by returning a void function? I'm not sure code like this should be allowed, as it doesn't really make sense to be able to return void (via a return statement) -- nothing is being returned.

Returning the result of a void function from a void function is accepted by design.

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--- Comment #3 from hsteoh@quickfur.ath.cx 2013-08-27 09:42:38 PDT ---
OK. Then it's purely just a wrong-code bug.

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Iain Buclaw <ibuclaw@ubuntu.com> changed:

           What    |Removed                     |Added
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                 CC|                            |ibuclaw@ubuntu.com


--- Comment #4 from Iain Buclaw <ibuclaw@ubuntu.com> 2013-08-27 10:32:41 PDT ---
(In reply to comment #2)
> (In reply to comment #1)
> 
> > I'm guessing perhaps the compiler got confused by returning a void function? I'm not sure code like this should be allowed, as it doesn't really make sense to be able to return void (via a return statement) -- nothing is being returned.
> 
> Returning the result of a void function from a void function is accepted by design.

Aye, but 'void main' is implicitly 'int main' - which is a special case in this instance. ;-)

All other types of void returns are ok to return garbage.

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