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std::bad_function_call(3)      C++ Standard Libary     std::bad_function_call(3)

NAME
     std::bad_function_call - std::bad_function_call

Synopsis
	Defined in header <functional>
	class bad_function_call;	(since C++11)

	std::bad_function_call is the type of the exception thrown by
	std::function::operator() if the function wrapper has no target.

	std-bad function call-inheritance.svg

					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().

	1) Default constructor.
	2) Copy constructor. If *this and other both have dynamic type
	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   )
     (since C++11)
	noexcept;

	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.

Parameters
	(none)

Return value
	Pointer  to  a	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.

Notes
	Implementations are allowed but not required to override what().

     Inherited from std::exception

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

Example
     // Run this code

      #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

See also
	function wraps callable object of any copy constructible type with spec-
     ified
	(C++11)  function call signature
		 (class template)

http://cppreference.com 	   2024.06.10	       std::bad_function_call(3)
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