std::experimental::scope_fail<EF>::scope_fail

 

C++

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Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

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Regular expressions library (C++11)

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Technical Specifications

 

Technical specifications

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals TS v2)

Library fundamentals 3 (library fundamentals TS v3)

Extensions for parallelism (parallelism TS)

Extensions for parallelism 2 (parallelism TS v2)

Extensions for concurrency (concurrency TS)

Concepts (concepts TS)

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Mathematical special functions (special functions TR)

 

Library fundamentals v3

experimental::scope_exit

experimental::scope_fail

experimental::scope_success

experimental::unique_resource

 

std::experimental::scope_fail

Member functions

scope_fail::scope_fail

scope_fail::~scope_fail

Modifiers

scope_fail::release

Deduction guides

 

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

Creates a scope_fail from a function, a function object or another scope_fail.

1) Initializes the exit function with a function or function object, and initializes the counter of uncaught exceptions as if with std::uncaught_exceptions(). The constructed scope_fail 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 only participates in overload resolution if std::is_same_v<std::remove_cvref_t<Fn>, scope_fail> is false and std::is_constructible_v<EF, Fn> is true.

The behavior is undefined if

• Fn&& is neither a reference to function nor a reference to function object, or
• the function call expression fn() is ill-formed, or
• 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, and initializes the counter of uncaught exceptions with the one in other. The constructed scope_fail 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 only participates in overload resolution 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) scope_fail is not CopyConstructible.

Parameters

fn	-	function or function object used for initializing the stored EF
other	-	scope_fail to move from

Exceptions

Any exception thrown during the initialization of the stored EF.

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>)

See also

uncaught_exceptionuncaught_exceptions (removed in C++20)(C++17)	checks if exception handling is currently in progress (function)
release	makes the scope_fail inactive (public member function)