std::error_code::assign

void assign (int val, const error_category& cat) noexcept;

Assign error code

Assigns the error_code object a value of val associated with the error_category cat.

The assignment operator (=) can be used to assign a new value to the error_code object by using an enum value instead.

Parameters

val: A numerical value identifying an error code.
cat: A reference to an error_category object.

Return value

none

Example

// error_code::assign
#include <iostream>       // std::cout
#include <cerrno>         // errno
#include <system_error>   // std::error_code, std::generic_category
#include <cmath>          // std::pow

struct expnumber {
  double value;
  std::error_code error;
  expnumber (double base, double exponent) {
    value = std::pow(base,exponent);
    if (errno) error.assign (errno,std::generic_category());
  }
};

int main()
{
  expnumber foo (3.0, 2.0);
  std::cout << foo.value << "\t" << foo.error.message() << '\n';

  expnumber bar (3.0, 10e6);
  std::cout << bar.value << "\t" << bar.error.message() << '\n';

  return 0;
}

Possible output:

9       No error
inf     Result too large

std::error_code::assign

Parameters

Return value

Example

See also