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Re: [std-proposals] finally keyword

From: Richard Hodges <hodges.r_at_[hidden]>
Date: Sun, 1 May 2022 12:11:24 +0200
On Sun, 1 May 2022 at 12:02, Abdullah Qasim <
iamminecraftredstoner_at_[hidden]> wrote:

> Why oppose a good feature??
>

It's not a good feature, it's a regression. The language already offers a
more robust solution.


>
>
> Finally is already implemented by Microsoft, so implementation difficulty
> = 0
>

>
> *From: *Richard Hodges via Std-Proposals <std-proposals_at_[hidden]>
> *Sent: *01 May 2022 14:59
> *To: *std-proposals_at_[hidden]
> *Cc: *Richard Hodges <hodges.r_at_[hidden]>
> *Subject: *Re: [std-proposals] finally keyword
>
>
>
>
>
>
>
> On Sun, 1 May 2022 at 10:10, Abdullah Qasim via Std-Proposals <
> std-proposals_at_[hidden]> wrote:
>
> If exception is thrown, no destructor is called.
>
>
>
> Use a unique_ptr with a custom deleter to act as your "finally" clause.
> Other languages have it because they don't support RAII.
>
> Here's an example:
>
> template<class Item ,class Deleter>
> auto make_finally(Item* item, Deleter del)
> {
> return std::unique_ptr<Item, Deleter>(item, std::move(del));
> }
>
> extern void do_log(FILE* fp, std::string const& contents);
>
> void append_file(std::filesystem::path const& p, std::string const& line)
> {
> auto fin1 = make_finally(::fopen(p.c_str(), "wb+"), &::fclose);
> try
> {
> do_log(fin1.get(), line);
> }
> catch(...)
> {
> // handle error here
> }
>
> // finally happens here
> }
>
>
>
>
>
> ***MEMORY LEAK ALERT***
>
>
>
> Finally is used for tasks performed regardless of thrown exception, but
> when exception is caught, control jumps to finally block.
>
>
>
> Useful!
>
>
>
> *From: *Peter C++ via Std-Proposals <std-proposals_at_[hidden]>
> *Sent: *01 May 2022 13:04
> *To: *std-proposals_at_[hidden]
> *Cc: *Peter C++ <peter.cpp_at_[hidden]>
> *Subject: *Re: [std-proposals] finally keyword
>
>
>
> that is a feature what destructors and SBRM are fir
>
>
>
> available in standard library extensions TS2, as scope guards, but not
> approved to std for the better.(I am the author)
>
>
>
> if there is a simple enough library solution, why should there be a
> language extension.
>
>
>
> watch a recording of one of my "what classes we design and how" to learn
> when destructors and clean up are actually desirable.
>
> sent from a mobile device so please excuse strange words due to
> autocorrection.
>
> Peter Sommerlad
>
> peter.cpp_at_[hidden]
>
> +41-79-432 23 32
>
>
>
> On 1 May 2022, at 09:52, Abdullah Qasim via Std-Proposals <
> std-proposals_at_[hidden]> wrote:
>
> 
>
>
>
> try {
>
> something();
>
> } catch (...) {
>
> std::cerr << "exception caught!!";
>
> }
>
>
>
> std::clog << "No except caught!";
>
>
>
> finally { // already Microsoft extension, but
>
> cleanup(); // should be in core language
>
> }
>
>
>
>
>
> --
> Std-Proposals mailing list
> Std-Proposals_at_[hidden]
> https://lists.isocpp.org/mailman/listinfo.cgi/std-proposals
>
>
>
> --
> Std-Proposals mailing list
> Std-Proposals_at_[hidden]
> https://lists.isocpp.org/mailman/listinfo.cgi/std-proposals
>
>
>

Received on 2022-05-01 10:11:36