std:: runtime_error
|
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 cannot be easily predicted.
Inheritance diagram
Exceptions of type
std::runtime_error
are thrown by the following standard library components:
| (since C++20) |
In addition, the following standard exception types are derived from
std::runtime_error
:
| (since C++11) |
| (since C++17) |
| (since C++20) |
Member functions
|
(constructor)
|
constructs a new
runtime_error
object with the given message
(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) |
std::runtime_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
Notes
Because copying
std::runtime_error
is not permitted to throw exceptions, this message is typically stored internally as a separately-allocated reference-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 object 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 assignment. 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 defined as long as the explanatory strings obtained by
what()
are the same for the original object and the copied object.
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
)
|
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 254 | C++98 | the constructor accepting const char * was missing | added |
| LWG 471 | C++98 |
the explanatory strings of
std::runtime_error
's
copies were implementation-defined |
they are the same as that of the
original
std::runtime_error
object
|