std::runtime_error
Defined in header <stdexcept>
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class runtime_error; |
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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
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&&
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
After the resolution of LWG issue 471
what()
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
Parameters
| other | - | another exception object to assign with |
Return value
*this
Notes
After the resolution of LWG issue 471
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) |
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'scopies were implementation-defined |
they are the same as that of the original std::runtime_error object
|