std::future_error - cppreference.com (original) (raw)

| | | | | -------------------- | | ------------- | | class future_error; | | (since C++11) |

The class std::future_error defines an exception object that is thrown on failure by the functions in the thread library that deal with asynchronous execution and shared states (std::future, std::promise, etc). Similar to std::system_error, this exception carries an error code compatible with std::error_code.

std-future error-inheritance.svg

Inheritance diagram

Contents

[edit] Member functions

| | creates a std::future_error object (public member function) [edit] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | replaces the std::future_error object (public member function) [edit] | | | returns the error code (public member function) [edit] | | | returns the explanatory string specific to the error code (public member function) [edit] |

Inherited from std::logic_error

Inherited from std::exception

Member functions

| | destroys the exception object (virtual public member function of std::exception) [edit] | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | returns an explanatory string (virtual public member function of std::exception) [edit] |

[edit] Example

#include #include   int main() { std::future empty; try { int n = empty.get(); // The behavior is undefined, but // some implementations throw std::future_error } catch (const std::future_error& e) { std::cout << "Caught a future_error with code "" << e.code() << ""\nMessage: "" << e.what() << ""\n"; } }

Possible output:

Caught a future_error with code "future:3" Message: "No associated state"

[edit] See also