GeezerVison is showing cplusplus.com — std::error_code::error_code
classes
enum classes
functions
public member function
<system_error>
| (1) | error_code() noexcept; |
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| (2) | error_code (int val, const error_category& cat) noexcept; |
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| (3) | template <class ErrorCodeEnum> error_code (ErrorCodeEnum e) noexcept; |
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Construct error_code
Constructs an error_code object:
- default constructor (1)
- Error code with a value of 0 of the system_category (generally indicating no error).
- initialization constructor (2)
- Error code with a value of val of the category specified by cat.
- construct from error code enum type (3)
- Calls make_error_code to construct an error code.
This constructor only participates in overload resolution if is_error_code_enum<ErrorCodeEnum>::value is true.
Parameters
- val
- A numerical value identifying an error code.
- cat
- A reference to an error_category object.
- e
- Error code enum value of an enum type for which is_error_code_enum has a value member with a value of true.
Example
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// error_code constructors
#include <iostream> // std::cout
#include <cmath> // std::sqrt
#include <cerrno> // errno
#include <system_error> // std::error_code, std::generic_category
// std::error_condition
int main()
{
errno=0;
std::sqrt(-1.0); // errno set to EDOM
std::error_code ec (errno,std::generic_category());
std::error_condition ok;
if (ec != ok) std::cout << "Error: " << ec.message() << '\n';
return 0;
}
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Possible output (cout):