Difference between revisions of "cpp/error/unexpected"
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{{cpp/error/navbar}} | {{cpp/error/navbar}} | ||
{{dcl begin}} | {{dcl begin}} | ||
| − | {{dcl header | exception}} | + | {{dcl header|exception}} |
{{dcl rev begin}} | {{dcl rev begin}} | ||
| − | {{dcl | until=c++11 | | + | {{dcl|until=c++11| |
void unexpected(); | void unexpected(); | ||
}} | }} | ||
| − | {{dcl | | + | {{dcl|deprecated=c++11|until=c++17| |
[[noreturn]] void unexpected(); | [[noreturn]] void unexpected(); | ||
}} | }} | ||
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{{dcl end}} | {{dcl end}} | ||
| − | {{tt|std::unexpected()}} is called by the C++ runtime when a [[cpp/language/ | + | {{tt|std::unexpected()}} is called by the C++ runtime when a [[cpp/language/except spec|dynamic exception specification]] is violated: an exception is thrown from a function whose exception specification forbids exceptions of this type. |
{{tt|std::unexpected()}} may also be called directly from the program. | {{tt|std::unexpected()}} may also be called directly from the program. | ||
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{{rev begin}} | {{rev begin}} | ||
{{rev|until=c++11| | {{rev|until=c++11| | ||
| − | If a destructor reset the unexpected handler during stack unwinding and the unwinding later led to {{tt|unexpected}} being called, the handler that was installed at the end of the throw expression is the one that will be called | + | If a destructor reset the unexpected handler during stack unwinding and the unwinding later led to {{tt|unexpected}} being called, the handler that was installed at the end of the throw expression is the one that will be called (note: it was ambiguous whether re-throwing applied the new handlers). |
}} | }} | ||
| − | {{rev|since=c++ | + | {{rev|since=c++11| |
If a destructor reset the unexpected handler during stack unwinding, it is unspecified which handler is called if the unwinding later led to {{tt|unexpected}} being called. | If a destructor reset the unexpected handler during stack unwinding, it is unspecified which handler is called if the unwinding later led to {{tt|unexpected}} being called. | ||
}} | }} | ||
{{rev end}} | {{rev end}} | ||
| + | ===Exceptions=== | ||
| + | Throw any exception thrown by the currently installed {{lc|std::unexpected_handler}}. | ||
| − | === | + | ===Defect reports=== |
| − | + | {{dr list begin}} | |
| − | + | {{dr list item|wg=lwg|dr=2111|std=C++11|before=effect of calling {{lc|std::set_unexpected}} during stack<br>unwinding differs from C++98 and breaks some ABIs|after=made unspecified}} | |
| − | === | + | {{dr list end}} |
| − | + | ||
| − | + | ||
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| − | + | ||
===See also=== | ===See also=== | ||
{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc inc | cpp/error/dsc unexpected_handler}} | + | {{dsc inc|cpp/utility/expected/dsc unexpected}} |
| + | {{dsc inc|cpp/error/dsc unexpected_handler}} | ||
{{dsc end}} | {{dsc end}} | ||
| − | + | {{langlinks|de|es|fr|it|ja|ru|zh}} | |
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Latest revision as of 03:48, 20 August 2024
| Defined in header <exception>
|
||
| void unexpected(); |
(until C++11) | |
| [[noreturn]] void unexpected(); |
(deprecated in C++11) (removed in C++17) |
|
std::unexpected() is called by the C++ runtime when a dynamic exception specification is violated: an exception is thrown from a function whose exception specification forbids exceptions of this type.
std::unexpected() may also be called directly from the program.
In either case, std::unexpected calls the currently installed std::unexpected_handler. The default std::unexpected_handler calls std::terminate.
|
If a destructor reset the unexpected handler during stack unwinding and the unwinding later led to |
(until C++11) |
|
If a destructor reset the unexpected handler during stack unwinding, it is unspecified which handler is called if the unwinding later led to |
(since C++11) |
[edit] Exceptions
Throw any exception thrown by the currently installed std::unexpected_handler.
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2111 | C++11 | effect of calling std::set_unexpected during stack unwinding differs from C++98 and breaks some ABIs |
made unspecified |
[edit] See also
| (C++23) |
represented as an unexpected value (class template) |
| (deprecated in C++11)(removed in C++17) |
the type of the function called by std::unexpected (typedef) |
