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

NAME
     std::runtime_error - std::runtime_error

Synopsis
	Defined in header <stdexcept>
	class runtime_error;

	Defines  a  type  of object to be thrown as exception. It reports errors
     that are due
	to events beyond the scope of the program and can  not	be  easily  pre-
     dicted.

	Exceptions  of type std::runtime_error are thrown by the following stan-
     dard library
	components: std::locale::locale and std::locale::combine.

	In addition, the following standard exception types are derived from
	std::runtime_error:

	  * std::range_error
	  * std::overflow_error
	  * std::underflow_error

	  * std::regex_error	(since C++11)
	  * std::system_error

	  * std::chrono::ambiguous_local_time
	  * std::chrono::nonexistent_local_time   (since C++20)
	  * std::format_error

	std-runtime error-inheritance.svg

					Inheritance diagram

Member functions
	constructor   constructs a new runtime_error object with the given  mes-
     sage
		      (public member function)
	operator=     replaces the runtime_error object
		      (public member function)

     std::runtime_error::runtime_error

	runtime_error( const std::string& what_arg ); (1)
	runtime_error( const char* what_arg );	      (2)
	runtime_error( const runtime_error& other );  (3) (noexcept since C++11)

	1)  Constructs the exception object with what_arg as explanatory string.
     After
	construction, std::strcmp(what(), what_arg.c_str()) == 0.
	2) Constructs the exception object with what_arg as explanatory  string.
     After
	construction, std::strcmp(what(), what_arg) == 0.
	3) Copy constructor. If *this and other both have dynamic type std::run-
     time_error
	then  std::strcmp(what(), other.what()) == 0. No exception can be thrown
     from the
	copy constructor.

Parameters
	what_arg - explanatory string
	other	 - another exception object to copy

Exceptions
	1,2) May throw std::bad_alloc.

Notes
	Because copying std::runtime_error is not permitted to throw exceptions,
     this
	message is typically stored internally as a separately-allocated  refer-
     ence-counted
	string.  This  is also why there is no constructor taking std::string&&:
     it would have
	to copy the content anyway.

	Before the resolution of LWG issue 254,  the  non-copy	constructor  can
     only accept
	std::string. It makes dynamic allocation mandatory in order to construct
     a
	std::string object.

	After  the  resolution	of  LWG  issue 471, a derived standard exception
     class must have
	a publicly accessible copy constructor. It can be implicitly defined  as
     long as the
	explanatory strings obtained by what() are the same for the original ob-
     ject and the
	copied object.

     std::runtime_error::operator=

	runtime_error& operator=( const runtime_error& other );  (noexcept since
     C++11)

	Assigns  the  contents with those of other. If *this and other both have
     dynamic type
	std::runtime_error then std::strcmp(what(), other.what()) == 0 after as-
     signment. No
	exception can be thrown from the copy assignment operator.

Parameters
	other - another exception object to assign with

Return value
	*this

Notes
	After the resolution of LWG issue  471,  a  derived  standard  exception
     class must have
	a publicly accessible copy assignment operator. It can be implicitly de-
     fined as long
	as the explanatory strings obtained by what() are the same for the orig-
     inal object
	and the copied object.

     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)

	Defect reports

	The  following	behavior-changing  defect  reports were applied retroac-
     tively to
	previously published C++ standards.

	  DR	Applied to	  Behavior  as	published		 Correct
     behavior
	LWG 254 C++98	   the constructor accepting const	added
			   char* was missing
			   the	explanatory  strings  of	    they are the
     same as that of
	LWG 471 C++98	   std::runtime_error's 		the
			   copies   were    implementation-defined	original
     std::runtime_error
								object

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