std::experi...::scope_exit(3)

🌸 NAME 🌸

std::experimental::scope_exit::scope_exit — the constructors, bestie. This page lives in the C++ Standard Libary manual under the very abbreviated title std::experi...::scope_exit(3) (and yes, “Libary” is literally spelled like that there 😭 keep it).

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✨ Synopsis ✨

template< class Fn >
explicit scope_exit( Fn&& fn ) noexcept(/*see below*/);       (1) (library fundamentals TS v3)
scope_exit( scope_exit&& other ) noexcept(/*see below*/);     (2) (library fundamentals TS v3)
scope_exit( const scope_exit& ) = delete;                     (3) (library fundamentals TS v3)

Okay so this is all about creating a scope_exit from a function, a function object, or another scope_exit. That’s the whole plot 🎀

1. scope_exit( Fn&& fn ) — Initializes the exit function with a function or function object. The constructed scope_exit is active. If Fn is not an lvalue reference type and std::is_nothrow_constructible_v<EF, Fn> is true, the stored EF is initialized with std::forward<Fn>(fn); otherwise it is initialized with fn. If initialization of the stored EF throws an exception, calls fn(). This overload participates in overload resolution only if std::is_same_v<std::remove_cvref_t<Fn>, scope_exit> is false and std::is_constructible_v<EF, Fn> is true. The program is ill-formed if function call expression fn() is ill-formed. The behavior is undefined if calling fn() throws an exception or results in undefined behavior, even if fn has not been called.
2. Move constructor — Initializes the stored EF with the one in other. The constructed scope_exit is active if and only if other is active before the construction. If std::is_nothrow_move_constructible_v<EF> is true, initializes stored EF (denoted by exitfun) with std::forward<EF>(other.exitfun), otherwise initializes it with other.exitfun. After successful move construction, other.release() is called and other becomes inactive. This overload participates in overload resolution only if std::is_nothrow_move_constructible_v<EF> is true or std::is_copy_constructible_v<EF> is true. The behavior is undefined if:
   • std::is_nothrow_move_constructible_v<EF> is true and EF does not meet the requirements of MoveConstructible, or
   • std::is_nothrow_move_constructible_v<EF> is false and EF does not meet the requirements of CopyConstructible.
3. Copy constructor is deleted — scope_exit is not CopyConstructible. Periodt 💅

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🎀 Parameters 🎀

• fn — function or function object used for initializing the stored EF
• other — scope_exit to move from

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💜 Exceptions 💜

Any exception thrown during the initialization of the stored EF. That’s the exception mood, no cap 😭

1) noexcept specification:

noexcept(std::is_nothrow_constructible_v<EF, Fn> ||
         std::is_nothrow_constructible_v<EF, Fn&>)

2) noexcept specification:

noexcept(std::is_nothrow_move_constructible_v<EF> ||
         std::is_nothrow_copy_constructible_v<EF>)

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🦋 Example 🦋

This section is incomplete Reason: no example

Not me being left with no example to vibe with 🙈

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🌈 See also 🌈

• release — makes the scope_exit inactive (public member function)

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🌟 Categories 🌟

• conditionally noexcept
• Todo no example

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okay that’s the whole page, bestie 💖 source/version + date time: http://cppreference.com · 2024.06.10 · this page: std::experi...::scope_exit(3) — slay and goodbye ✨🫶