Re: A: a new bug to old plain C

no they are not, they are a WIKIfication of the C specification, in
particular the heading "Why am I getting an error converting a Foo** →
const Foo**?" in an official FAQ from the C Standards Committee should make
you realize this.

/HH

Den mån 24 nov. 2025 kl 18:45 skrev Александр Поваляев <[email protected]
>:

> The articles mentioned are all about coding practices ("safe" and
> "unsafe"). They are not about bugs in compilers and hard restrictions being
> placed on where I can use "const" in my code and where I can't. :)
>
> The links mentioned earlier just give a recommendation to use "Foo** ->
> const Foo * const *" conversion instead of "Foo** -> const Foo**".
> Literally, what I am saying is that: "if you can use const, you should use
> it". And this is the case which just confirms my attitude.
> But again, this is about coding practices and recommendations. There is no
> place in C and C++ standards saying "DON"T USE CONST EVEN IF YOU CAN DO IT.
> WE'RE PROHIBITING THIS".
>
> And so, what GCC compiler (+ some SDKs) is doing now is just the opposite
> to the recommendation mentioned. It restricts the places where "const"
> might be used.
> Anyway, it is a BUG (BIG BUG!!!) in the GCC + SDK. And the BUG was not
> made intentionally to protect software engineers from using "unsafe coding
> practices" :)))))
> For such kind of practices, there are warnings with information messages.
> And the bug in GCC should be (1) reported; (2) nailed down and (3) fixed.
>
> Respectfully,
> Aleksandr G Povaliaev.
>
>
> пн, 24 нояб. 2025 г. в 16:10, Henrik Holst <[email protected]>:
>
>>
>>
>> Den mån 24 nov. 2025 kl 13:40 skrev Александр Поваляев <
>> [email protected]>:
>>
>>> Hi there!
>>>
>>> "False sense of security". Const is a hint to any C compiler to make
>>> code more error-prone. So, it is always better to use as much "const" as
>>> possible.
>>> My point is that "if const might be used, it SHOULD be used". That is
>>> the cornerstone.
>>> I want to use it, so GCC compiler + SDK should make it possible. It is
>>> my code and my design decisions being undertaken.
>>>
>>> All discussions if it is possible to overcome or not "Const" restriction
>>> is irrelivant here.
>>>
>> no it is not irrelevant here because if I declare a variable as const in
>> my local code the value should not be changed by other code either, look at
>> the code in the link given to you earlier which shows just such a case as
>> an example on why this is not allowed in C.
>>
>> /HH
>>
>>>
>>> Respectfully,
>>> Aleksandr G Povaliaev.
>>>
>>> пн, 24 нояб. 2025 г. в 13:46, Henrik Holst <[email protected]
>>> >:
>>>
>>>> The things is that this is unsafe and invalid due to it creating a
>>>> false sense of security. Aka your "const Foo *" can change under your feet
>>>> by _other_ code leading to your const here giving you a false sense of
>>>> security. Yes it prevents you from modifying it locally but not some other
>>>> code or thread from modifying your const pointer to now point to something
>>>> else, hence the compiler issues an error here since you do not get what you
>>>> think you are getting.
>>>>
>>>> /HH
>>>>
>>>> Den mån 24 nov. 2025 kl 11:10 skrev Александр Поваляев via Gcc-help <
>>>> [email protected]>:
>>>>
>>>>> Hi there!
>>>>>
>>>>> The code is not invalid and neither of the links posted saying that
>>>>> "const
>>>>> Foo * const * const" is invalid construction for C.
>>>>> The links posted just are discussing that it might be UNSAFE to cast
>>>>> "Foo
>>>>> **" -> "const Foo **" and recommending usage of "Foo **" -> "const Foo
>>>>> *
>>>>> const *" instead.
>>>>> It's OK. If you feel that it is unsafe, please don't use it. It is
>>>>> your own
>>>>> decision.
>>>>>
>>>>> But the syntax itself "const Foo * const * const" is correct and the
>>>>> use-case I mentioned is quite simple and evident.
>>>>> And so I need this code snipped to be compiled transparently over all
>>>>> the
>>>>> GCC (and platform SDKs) available versions.
>>>>>
>>>>> Respectfully,
>>>>> Aleksandr G Povaliaev.
>>>>>
>>>>>
>>>>> пн, 24 нояб. 2025 г. в 01:48, David Brown <[email protected]>:
>>>>>
>>>>> > On 23/11/2025 21:45, Александр Поваляев via Gcc-help wrote:
>>>>> > > Hi there!
>>>>> > >
>>>>> >
>>>>> > This is getting /extremely/ frustrating.  /Please/ find some way to
>>>>> > learn the C programming language - courses, books, good online
>>>>> resources.
>>>>> >
>>>>> > And /please/ believe me when I say that people who have worked with C
>>>>> > and C++ for decades, studied the standards, who serve on the
>>>>> standards
>>>>> > committee, know better about these things than you do.  (I'm talking
>>>>> > about Jonathan here, not myself - he really is a world-class expert
>>>>> here.)
>>>>> >
>>>>> > > Either the links you've provided or the links you provided earlier
>>>>> > > (yesterday) are irrelevant, cause they are just discussing if it
>>>>> is safer
>>>>> > > to convert "Foo_Type **" to "const Foo_Type **" or not.
>>>>> > >
>>>>> >
>>>>> > The links are highly relevant.  They explain why you cannot convert
>>>>> from
>>>>> > "char **" to "const char **".  That also explains why you cannot
>>>>> convert
>>>>> > from "char **" to "const char * const * const".  Adding even more
>>>>> > "const" qualifiers to the invalid conversion does not somehow
>>>>> magically
>>>>> > make it work.
>>>>> >
>>>>> > > Once again, we are not converting "char** to const char**", we're
>>>>> > > converting char** to const char * const * const".
>>>>> > > And we're not discussing if it is safer or not, we are discussing
>>>>> GCC
>>>>> > > compiler error.
>>>>> > >
>>>>> >
>>>>> > The compiler is generating an error message because you wrote invalid
>>>>> > code.  The error - or bug, if you like - is in /your/ code.  Not the
>>>>> > compiler.  GCC is doing its job correctly here.
>>>>> >
>>>>> > >
>>>>> > > Respectfully,
>>>>> > > Aleksandr G Povaliaev.
>>>>> > >
>>>>> >
>>>>> > I'm sorry, but signing the post with "respectfully" does not make it
>>>>> > respectful.  You started the thread disrespectfully - insisting that
>>>>> > there is a bug in GCC when you simply do not understand the relevant
>>>>> > aspects of the C programming language.  And you have gone downhill
>>>>> since
>>>>> > then, ignoring and rejecting the help and advice you have been given.
>>>>> > Getting things wrong once is entirely understandable - this is a
>>>>> subtle
>>>>> > point of the C language, and you are posting to a "help" list.
>>>>> Doubling
>>>>> > down on your ignorance when you have received the help and
>>>>> information
>>>>> > you need, is a different matter entirely.
>>>>> >
>>>>> > Your code is flawed.  You need to fix it.  Mindlessly repeating your
>>>>> > misunderstandings about how you think C works will not do anything
>>>>> but
>>>>> > annoy people.
>>>>> >
>>>>> > David
>>>>> >
>>>>> >
>>>>>
>>>>