Subject: Re: CYGWIN + windos10 + eclipse clp prolog
From: Brian Inglis <[email-masked]>
To: [email-masked]
Cc: Manu goswami <[email-masked]>
Date: Sat, 31 Jul 2021 09:56:03 -0600
List-Id: General Cygwin discussions and problem reports <cygwin.cygwin.com>

On 2021-07-30 22:55, Manu goswami via Cygwin wrote:
> On Thursday, July 29, 2021 5:29:58 PM, Manu goswami wrote:
>> On Thursday, July 29, 2021 1:08 PM, Brian Inglis wrote:
>>> On 2021-07-28 02:03, Manu goswami via Cygwin wrote:
>>>>> I have previously build eclipse clp prolog several times in
>>>>> CYGWIN but suddenly it has started to show ‘SEGMENTATION
>>>>> FAULT’ even after fully reinstalling CYGWIN and removing
>>>>> (manually deleting) old Cygwin.  No error is reported at
>>>>> build time and .exe is successfully generated but on
>>>>> execution of .exe file after build shows ‘ SEGMENTATION
>>>>> FAULT’.

>>>> If you want to see replies to your questions, subscribe to the
>>>> mailing list, or view the replies on one of the many web based
>>>> message archives of the mailing list, including that at
>>>> cygwin.com.
>>>> 
>>>> Report upstream to wherever you got the sources for whatever
>>>> "eclipse clp prolog" is - in whatever language(s) they use -
>>>> web links to projects and sources are more informative than
>>>> garbled buzzwords.
>>>> 
>>>> SIGSEGV is a symptom of a programming error - out of bounds 
>>>> access - caused by following the wrong pointer to an invalid 
>>>> location, using a NULL pointer, array or buffer index 
>>>> incorrect, use after free, incorrect object size or
>>>> indirection, just to suggest some of the most frequent and
>>>> common causes.
>>>> 
>>>> If you have made your own local and/or recent changes to the 
>>>> sources, they are invariably the likely cause of the issue, so 
>>>> recheck any recent local work very carefully.
>>>> 
>>>> The Cygwin project provides packages for execution and
>>>> development but, as Cygwin is an all volunteer effort, with
>>>> limited personnel each with limited time, so all projects built
>>>> using those packages are the responsibility of those projects
>>>> downstream of Cygwin, otherwise we would not have any time to
>>>> maintain and expand the packages supported.

>>> Eclipse clp is a version of open source prolog and had been
>>> running successfully on my computer for some months.
>>> 
>>> There has been no change in source code.
>>> 
>>> What new I did was to install msys2 and call a particular Cygwin 
>>> compiled exe from msys2. The called Cygwin compiled  .exe did run
>>> from msys2 but most probably crashed Cygwin causing segmentation
>>> fault ever since. Surprisingly the called Cygwin compiled .exe
>>> runs successfully but eclipse clp prolog .exe fails.
>>> 
>>> Should I remove msys2 ? as I have reinstalled Cygwin multiple
>>> times ever since this error occurs.

>> That's the only recent local change, but the Msys2 DLLs are often
>> outdated Cygwin derivatives, and Cygwin programs may try to call
>> functions nonexistent in Msys2 DLLs.
>> The situation can be mitigated by setting the path to run the 
>> Cygwin compiled code using the Cygwin DLLs from the Cygwin bin,
>> and changing the path to run the Msys2 tools using the DLLs from
>> the Msys2 bin.
> Yes, you were right. The problem was upstream in Eclipse Prolog 
> Source code. Has been resolved now. You may consider the issue
> closed.
> > Only one query. Cygwin is a good idea and works well.  But is it
> weaker in GUI and multithreaded as compared to msys2? Kindly advise
As previously stated, Msys2 DLLs are often outdated Cygwin derivatives, 
focused on allowing development of Windows apps using GNU tools, so the 
Windows apps developed using those tools can make full use of Windows 
GUI and multithreaded facilities, but Cygwin is better than Msys2 in the 
respect of being more functional and up to date libraries and tools, as 
it provides a complete POSIX and Linux compatible layer over Windows, 
with over 10k packages including enough applications to support the 
common X clients, window managers, and desktop environments GNOME, KDE, 
LXDE, MATE, as well as command line and development tools and libraries 
for building POSIX sources into Cygwin apps, or native Windows apps 
requiring Mingw libraries and tools.

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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