std::bad_function_call
| Defined in header <functional>
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| class bad_function_call; |
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std::bad_function_call is the type of the exception thrown by std::function::operator() if the function wrapper has no target.
Inheritance diagram
Member functions
| (constructor) |
constructs a new bad_function_call object (public member function) |
| operator= |
replaces the bad_function_call object (public member function) |
| what |
returns the explanatory string (public member function) |
std::bad_function_call::bad_function_call
| bad_function_call() noexcept; |
(1) | (since C++11) |
| bad_function_call( const bad_function_call& other ) noexcept; |
(2) | (since C++11) |
Constructs a new bad_function_call object with an implementation-defined null-terminated byte string which is accessible through what().
std::bad_function_call then std::strcmp(what(), other.what()) == 0.Parameters
| other | - | another exception object to copy |
std::bad_function_call::operator=
| bad_function_call& operator=( const bad_function_call& other ) noexcept; |
(since C++11) | |
Assigns the contents with those of other.If *this and other both have dynamic type std::bad_function_call then std::strcmp(what(), other.what()) == 0 after assignment.
Parameters
| other | - | another exception object to assign with |
Return value
*this
std::bad_function_call::what
virtual const char* what() const noexcept; |
(since C++11) | |
Returns the explanatory string.
Return value
Pointer to an implementation-defined null-terminated string with explanatory information. The string is suitable for conversion and display as a std::wstring. The pointer is guaranteed to be valid at least until the exception object from which it is obtained is destroyed, or until a non-const member function (e.g. copy assignment operator) on the exception object is called.
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The returned string is encoded with the ordinary literal encoding during constant evaluation. |
(since C++26) |
Notes
Implementations are allowed but not required to override what().
Inherited from std::exception
Member functions
| [virtual] |
destroys the exception object (virtual public member function of std::exception) |
| [virtual] |
returns an explanatory string (virtual public member function of std::exception) |
Example
#include <functional> #include <iostream> int main() { std::function<int()> f = nullptr; try { f(); } catch (const std::bad_function_call& e) { std::cout << e.what() << '\n'; } }
Possible output:
bad function call
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 2233 | C++11 | what() always returned the same explanatorystring as std::exception::what() |
returns its own explanatory string |
See also
| (C++11) |
copyable wrapper of any copy constructible callable object (class template) |