Re: Application not working in 64-bit cygwin cygwin/X

[Kaz Kylheku <920-082-4242@kylheku.com>]

On 11.03.2016 22:27, Marco Atzeri wrote:
> On 12/03/2016 00:10, David Stacey wrote:
>> On 11/03/16 14:23, Girish Joglekar wrote:
>>> I have cleaned up the test example based on X-Windows/Motif which 
>>> crashes
>>> on 64-bit cygwin cygwin/X but runs on the 32-bit version. The only
>>> warnings are of the type 'variable set but not used'.
>>> 
>>> Here is the link to the tar file.
>>> 
>>> https://www.dropbox.com/s/lknuoac64hfql4s/test.tar?dl=0
>>> 
>>> Hope you can reproduce the behavior and fix the problem.
>> 
>> I tried this on Fedora 23 64-bit and it works. I had to add an empty
>> utcrcu.h file, as the code tries to #include this, and it doesn't 
>> exist
>> in the tar file. Given that it runs in 64-bit Linux, the problem is
>> unlikely to be an issue associated with porting 32-bit applications to
>> 64-bit.
>> 
>> Dave.
>> 
> it can be a bug not triggered on linux due the difference in managing
> function arguments in the stack.

Among a myriad other things! Undefined behaviors can have totally 
different consequences even on architecturally similar systems. E.g. a 
malloced
buffer overrun depends on the heap structure and allocation pattern
driven by program inputs. Uninitialized memory will have different 
garbage
in it. And so on.

So it works on Fedora 23 64-bit? That could be by fluke.

How about this: does it run with zero errors under Valgrind on the same 
system?

That represents a greater confidence that "it works".

In any case, this is a poor approach to problem solving in the
context of open source:

"Hi, on your platform the program in my multi-megabyte archive crashes
... somewhere in the code (I could tell you where, but I can't be 
bothered
to use the debugger). Please download the whole, reproduce the problem, 
and
debug it for me."

This kind of burp-and-diaper changing is done in the industry only for
paying customers.

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