[Info-vax] VMS Cobol - GnuCOBOL

[bill]

On 2/28/2023 6:39 AM, David Wade wrote:
> On 27/02/2023 23:35, Arne Vajhøj wrote:
>> On 2/27/2023 5:42 PM, David Wade wrote:
>>> On 27/02/2023 20:58, Arne Vajhøj wrote:
>>>> On 2/27/2023 11:49 AM, ultr... at gmail.com wrote:
>>>>> On Thursday, February 23, 2023 at 5:05:50 PM UTC-5, Paul Gavin wrote:
>>>>>> What, DEC C cannot be debugged?
>>>>>> Working on some enhancements in a C based app on Alphas running 8.4.
>>>>>> Can get to debugger just fine, step through code, look at data, 
>>>>>> set break points, etc., even from within ACMS.
>>>>>
>>>>> never debugged dec c but if the compiler debugger is anything like 
>>>>> C it is difficult ...
>>>>
>>>> The VMS C compiler behaves pretty much like other VMS compilers.
>>>>
>>>> The same VMS debugger is used for C as for any other 
>>>> (DEC/CPQ/HPE/VSI) language.
>>>
>>> I feel the issue with debugging "C" is that in order to effectively 
>>> use the debugger you tend to need to turn down optimisation, but 
>>> turning down optimization tends to make the code work as you expect. 
>>> When you turn it up again, undefined behaviour tends to re-emerge.
>>
>> /DEB/NOOP is not required but tend to make it easier to
>> debug because there is a closer correlation between the
>> instruction stream and the lines of source code.
>>
>> And as you point out then that can in fact by itself
>> remove symptoms of a bug.
>>
>> But isn't that the case for all VMS compilers? I know
>> I use /DEB/NOOP for both Fortran, Pascal and C when I want
>> to debug.
> 
> Of course, BUT I feel other languages have fewer places where undefined 
> behaviour can occur, and so the problem is not so severe.
> 

And then you have the case (it's been a long while but at one time
was very common in my experience) where turning off optimization
"fixes" the problem.

:-)

bill