std::experimental::scope_fail
| Defined in header <experimental/scope>
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| template< class EF > class scope_fail; |
(library fundamentals TS v3) | |
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.
Contents |
[edit] Template parameters
| EF | - | type of stored exit function |
| Type requirements | ||
-EF shall be either:
| ||
| -Calling an lvalue of std::remove_reference_t<EF> with no argument shall be well-formed. | ||
[edit] Member functions
constructs a new scope_fail (public member function) | |
calls the exit function when the scope is exited via an exception if the scope_fail is active, then destroys the scope_fail (public member function) | |
| operator= [deleted] |
scope_fail is not assignable (public member function) |
Modifiers | |
makes the scope_fail inactive (public member function) | |
[edit] Deduction guides
[edit] 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.
[edit] Example
| This section is incomplete Reason: no example |
[edit] See also
| wraps a function object and invokes it on exiting the scope (class template) | |
| wraps a function object and invokes it on exiting the scope normally (class template) | |
| (C++11) |
default deleter for unique_ptr (class template) |
