std::error_condition::error_condition

default constructor (1)

Error condition with a value of 0 of the generic_category (associated with lack of error).

initialization constructor (2)

Error condition with a value of val of the category specified by cat.

construct from error condition enum type (3)

Calls make_error_condition to construct an error code.
This constructor only participates in overload resolution if is_error_condition_enum<ErrorConditionEnum>::value is true. Which is the case when errc is used as the ErrorConditionEnum type.

Parameters

val

A numerical value identifying an error condition.

cat

A reference to an error_category object.

e

Error condition enum value of an enum type for which is_error_condition_enum has a value member with a value of true.
If this is a value of type errc, the object is set to the appropriate error condition value of the generic_category.

Example

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// error_condition::error_condition
#include <iostream>       // std::cout, std::ios
#include <system_error>   // std::error_condition, std::generic_category

int main() {
  std::cout << "The default error condition: ";
  std::cout << std::error_condition().message() << '\n';

  std::cout << "A condition constructed from errc: ";
  std::cout << std::error_condition(std::errc::permission_denied).message() << '\n';

  std::cout << "Some generic error conditions, by value:\n";
  for (int i=0; i<10; ++i) {
    std::error_condition c (i,std::generic_category());
    std::cout << "\t#" << i << ": " << c.message() << '\n';
  }
  return 0;
}

The default error condition: No error
A condition constructed from errc: Permission denied
Some generic error conditions, by value:
        #0: No error
        #1: Operation not permitted
        #2: No such file or directory
        #3: No such process
        #4: Interrupted function call
        #5: Input/output error
        #6: No such device or address
        #7: Arg list too long
        #8: Exec format error
        #9: Bad file descriptor

See also

error_condition::operator=

Assign error condition (public member function)

error_condition::assign

Assign error condition (public member function)

error_condition::clear

Clear error condition (public member function)