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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 adynamic 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 installedstd::unexpected_handler. The defaultstd::unexpected_handler callsstd::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) |
Throw any exception thrown by the currently installedstd::unexpected_handler.
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 callingstd::set_unexpected during stack unwinding differs from C++98 and breaks some ABIs | made unspecified |
(C++23) | represented as an unexpected value (class template)[edit] |
(deprecated in C++11)(removed in C++17) | the type of the function called bystd::unexpected (typedef)[edit] |
