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From: "johelegp at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/83258] Rejecting function pointer non-type template parameter without linkage
Date: Sat, 13 Mar 2021 21:51:22 +0000	[thread overview]
Message-ID: <bug-83258-4-UDOBMuhacV@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-83258-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83258

--- Comment #10 from Johel Ernesto Guerrero Peña <johelegp at gmail dot com> ---
Another workaround, extended from Bug 92320's example. See
https://godbolt.org/z/69onWf.
You can wrap the closure object in a template function which itself invokes the
closure object and converts to a function pointer that GCC accepts.
```C++
template<auto V>
void templ() {}

void dummy(){}

template<auto F>
void fn(){F();}

void foo() {
    constexpr int a = 7 + 3;
    templ<a>();

    templ<dummy>();

    typedef void(FPtr)();
    constexpr FPtr * b = &dummy;
    templ<b>();

    constexpr auto l = []{};
    constexpr void (*d)()=fn<l>;
    templ<d>();

    constexpr FPtr * c = [](){};
    templ<c>();
}

```

  parent reply	other threads:[~2021-03-13 21:51 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-83258-4@http.gcc.gnu.org/bugzilla/>
2020-03-17 18:17 ` herring at lanl dot gov
2020-08-26 15:51 ` ma.noack.pr at gmail dot com
2021-03-13 19:44 ` johelegp at gmail dot com
2021-03-13 21:51 ` johelegp at gmail dot com [this message]
2021-12-04  1:01 ` pinskia at gcc dot gnu.org
2021-12-20  4:10 ` egallager at gcc dot gnu.org
2023-05-11 14:05 ` cvs-commit at gcc dot gnu.org
2023-05-11 14:25 ` ppalka at gcc dot gnu.org
2023-05-12 12:38 ` cvs-commit at gcc dot gnu.org
2023-05-12 15:08 ` cvs-commit at gcc dot gnu.org
2023-05-12 15:08 ` cvs-commit at gcc dot gnu.org
2023-05-12 15:25 ` ppalka at gcc dot gnu.org

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