std::future_error

 

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std::future_error

Member functions

future_error::future_error

future_error::operator=

future_error::code

future_error::what

 

Defined in header <future>
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.

Inheritance diagram

Member functions

(constructor)	creates a std::future_error object (public member function)
operator=	replaces the std::future_error object (public member function)
code	returns the error code (public member function)
what	returns the explanatory string specific to the error code (public member function)

Inherited from std::logic_error

Inherited from std::exception

Member functions

(destructor) [virtual]	destroys the exception object (virtual public member function of std::exception)
what [virtual]	returns an explanatory string (virtual public member function of std::exception)

Example

Run this code

#include <future>#include <iostream>   int main(){std::future<int> 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"

See also

future_errc (C++11)

identifies the future error codes (enum)