D seems interesting, but...

[Gerry Weaver]

On Monday, 15 October 2012 at 20:45:39 UTC, Gerry Weaver wrote:
> On Monday, 15 October 2012 at 20:19:22 UTC, Gerry Weaver wrote:
>> On Monday, 15 October 2012 at 19:38:24 UTC, H. S. Teoh wrote:
>>> On Mon, Oct 15, 2012 at 08:46:21PM +0200, Gerry Weaver wrote:
>>> [...]
>>>> It just occurred to me that I've seen this type of file issue
>>>> before. If memory serves, it was related to the attempt to 
>>>> load a
>>>> 64bit lib on a 32bit system. It was an odd problem, because 
>>>> it
>>>> didn't fail in the way one would expect. The process in that 
>>>> case
>>>> was reading garbage from memory. I don't get how it could be 
>>>> reading
>>>> nothing though. Anyway, I'm going to look into this 
>>>> possibility. I
>>>> found some notes that I made during that time and it does 
>>>> have a
>>>> similar feel to it. I'll let y'all know what I find.
>>> [...]
>>>
>>> Now, that does sound like it could be the source of the 
>>> problem. If dmd
>>> was reading garbage from the file, if there just happens to 
>>> be, say, a
>>> binary 0 at the beginning (or whatever it is that causes dmd 
>>> to think it
>>> has reached EOF), then it would just stop and produce an 
>>> empty object
>>> file. So the linker will fail to find the symbols that dmd 
>>> emits when it
>>> encounters main().
>>>
>>>
>>> T
>>
>> Hi,
>>
>> When running dmd, none of the read (and friends) syscalls 
>> happen as far as the kernel is concerned. This would lend some 
>> credibility to the lib theory. However, it's quite odd that 
>> results are the same for each time dmd is executed. I would 
>> expect a random result or even a segfault/abort on different 
>> runs.
>>
>> Thanks,
>> -G
>
> Hi,
>
> I think I have satisfied myself that this is probably a fluke. 
> We have captured enough in this thread that there will be a 
> good starting point should the issue ever come up again. It may 
> sound odd, but I'm actually glad it happened. It helped me 
> realize an issue with a system that would probably have 
> manifested itself in some other frustrating and embarrassing 
> way later on ;-)
>
> Thanks everyone,
> -G

Hi,

Sorry, I neglected to mention something. I did a test with a zero 
length file and compared the output to the problem case. The 
output was, in fact, identical. Would it be difficult to do a 
simple test for zero length files and output a message like 
"error: zero length/empty file <filename>"? The output in this 
case is fairly misleading.

Thanks,
-G