std::bad_function_call
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Defined in header <functional> | ||
class bad_function_call; | ||
std::bad_function_call is the type of the exception thrown bystd::function::operator() if the function wrapper has no target.
Inheritance diagram
Contents |
[edit]Member functions
(constructor) | constructs a newbad_function_call object(public member function) |
operator= | replaces thebad_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 newbad_function_call object with an implementation-defined null-terminated byte string which is accessible throughwhat().
std::bad_function_call thenstd::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 ofother. If*this andother both have dynamic typestd::bad_function_call thenstd::strcmp(what(), other.what())==0 after assignment.
Parameters
| other | - | another exception object to assign with |
Return value
*this
std::bad_function_call::what
virtualconstchar* what()constnoexcept; | (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 astd::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.
Notes
Implementations are allowed but not required to overridewhat().
Inherited fromstd::exception
Member functions
[virtual] | destroys the exception object (virtual public member function of std::exception)[edit] |
[virtual] | returns an explanatory string (virtual public member function of std::exception)[edit] |
[edit]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
[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 2233 | C++11 | what() always returned the same explanatorystring asstd::exception::what() | returns its own explanatory string |
[edit]See also
(C++11) | copyable wrapper of any copy constructible callable object (class template)[edit] |
