NAME¶

std::experimental::scope_fail - std::experimental::scope_fail

Synopsis¶

Defined in header <experimental/scope>
template<class EF> (library fundamentals TS v3)
class scope_fail;

The class template scope_fail is a general-purpose scope guard intended to call its
exit function when a scope is exited via an exception.

scope_fail is not CopyConstructible, CopyAssignable or MoveAssignable, however, it
may be MoveConstructible if EF meets some requirements, which permits wrapping a
scope_fail into another object.

A scope_fail may be either active, i.e. calls its exit function on destruction, or
inactive, i.e. does nothing on destruction. A scope_fail is active after constructed
from an exit function.

A scope_fail can become inactive by calling release() on it either manually or
automatically (by the move constructor). An inactive scope_fail may also be obtained
by initializing with another inactive scope_fail. Once a scope_fail is inactive, it
cannot become active again.

A scope_fail effectively holds an EF and a bool flag indicating if it is active,
alongwith a counter of uncaught exceptions used for detecting whether the destructor
is called during stack unwinding.

Template parameters¶

EF - type of stored exit function

Type requirements¶

-
EF shall be either:

* a Destructible FunctionObject type
* an lvalue reference to FunctionObject
* an lvalue reference to function
-
Calling an lvalue of std::remove_reference_t<EF> with no argument shall be
well-formed.

Member functions¶

constructor constructs a new scope_fail
(public member function)
calls the exit function when the scope is exited via an exception if
destructor the scope_fail is active, then destroys the scope_fail
(public member function)
operator= scope_fail is not assignable
[deleted] (public member function)

Modifiers¶

release makes the scope_fail inactive
(public member function)

Deduction guides

Notes¶

Constructing a scope_fail of dynamic storage duration might lead to unexpected
behavior.

Constructing a scope_fail is constructed from another scope_fail created in a
different thread might also lead to unexpected behavior since the count of uncaught
exceptions obtained in different threads may be compared during the destruction.

Example¶

This section is incomplete
Reason: no example

See also¶

scope_exit wraps a function object and invokes it on exiting the scope
(class template)
scope_success wraps a function object and invokes it on exiting the scope normally
(class template)
default_delete default deleter for unique_ptr
(C++11) (class template)