add_noexcept.hpp

#ifndef UT_ADD_NOEXCEPT_H
#define UT_ADD_NOEXCEPT_H

namespace ut {
/* Add noexcept to function type
 *
 * std >= c++17
 */

/* Usage:
 *
 * int foo() noexcept {
 *     return 42;
 * }
 *
 * int main() {
 *     int (*foo_ptr)() = foo; // OK. can implicitly convert from noexcept function to throwing function
 *
 *     // int (*foo_ptr_noexcept)() noexcept = foo_ptr; // Error. can't implicitly convert the other way
 *
 *     int (*foo_ptr_noexcept)() noexcept = ut::noexcept_cast(foo_ptr);
 *
 * }
 */
template<typename F>
struct add_noexcept;

template<typename Ret, typename... Args>
struct add_noexcept<Ret(Args...)> {
    using type = Ret(Args...) noexcept;
};

template<typename Ret, typename... Args>
struct add_noexcept<Ret(Args...) noexcept> {
    using type = Ret(Args...) noexcept;
};

template<typename T>
using add_noexcept_t = typename add_noexcept<T>::type;

/// Using this is almost always UB

template<typename T>
[[nodiscard]]
add_noexcept_t<T> *noexcept_cast(T *fn) noexcept {
    return reinterpret_cast<add_noexcept_t<T> *>(fn);
}
}  // namespace ut

/*
This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or
distribute this software, either in source code form or as a compiled
binary, for any purpose, commercial or non-commercial, and by any
means.

In jurisdictions that recognize copyright laws, the author or authors
of this software dedicate any and all copyright interest in the
software to the public domain. We make this dedication for the benefit
of the public at large and to the detriment of our heirs and
successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to <https://unlicense.org>
*/
#endif  // UT_ADD_NOEXCEPT_H

zzz_description

add the `noexcept` specifier to a function type