std::invalid_argument
Defined in header <stdexcept>
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class invalid_argument; |
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Defines a type of object to be thrown as exception. It reports errors that arise because an argument value has not been accepted.
This exception is thrown by std::bitset::bitset, and the std::stoi and std::stof
Inheritance diagram
Member functions
(constructor) |
constructs a new invalid_argument object with the given message (public member function) |
operator= |
replaces the invalid_argument object (public member function) |
std::invalid_argument::invalid_argument
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invalid_argument(
const
std::string
& what_arg )
;
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(1) | |
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invalid_argument( const char* what_arg );
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(2) | |
invalid_argument( const invalid_argument& other ); |
(3) | (noexcept since C++11) |
std::invalid_argument then
std::strcmp
(what(
), other.what
(
)
)
==
0
Parameters
| what_arg | - | explanatory string |
| other | - | another exception object to copy |
Exceptions
Notes
Because copying std::invalid_argument 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::invalid_argument::operator=
|
invalid_argument& operator=
(
const invalid_argument& other )
;
|
(noexcept since C++11) | |
Assigns the contents with those of other. If *this and other both have dynamic type std::invalid_argument 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::logic_error
Inherited from std::exception
Member functions
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[virtual]
|
destroys the exception object (virtual public member function of std::exception) |
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[virtual]
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returns an explanatory string (virtual public member function of std::exception) |
Notes
The purpose of this exception type is similar to the error condition std::errc::invalid_argument (thrown in std::system_error from member functions of std::thread) and the related errno constant EINVAL
Example
#include <bitset> #include <iostream> #include <stdexcept> #include <string> int main() { try { std::bitset<4>{"012"}; // Throws: only '0' or '1' expected } catch (std::invalid_argument const& ex) { std::cout << "#1: " << ex.what() << '\n'; } try { [[maybe_unused]] int f = std::stoi("ABBA"); // Throws: no conversion } catch (std::invalid_argument const& ex) { std::cout << "#2: " << ex.what() << '\n'; } try { [[maybe_unused]] float f = std::stof("(3.14)"); // Throws: no conversion } catch (std::invalid_argument const& ex) { std::cout << "#3: " << ex.what() << '\n'; } }
Possible output:
#1: bitset string ctor has invalid argument #2: stoi: no conversion #3: stof: no conversion
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::invalid_argument'scopies were implementation-defined |
they are the same as that of the original std::invalid_argument object
|