value::to_number (2 of 3 overloads)

Return the stored number cast to an arithmetic type.

template<
    class T>
T
to_number(
    std::error_code& ec) const;

This function attempts to return the stored value converted to the arithmetic type T which may not be bool:

If T is an integral type and the stored value is a number which can be losslessly converted, the conversion is performed without error and the converted number is returned.
If T is an integral type and the stored value is a number which cannot be losslessly converted, then the operation fails with an error.
If T is a floating point type and the stored value is a number, the conversion is performed without error. The converted number is returned, with a possible loss of precision.
Otherwise, if the stored value is not a number; that is, if this->is_number() returns false, then the operation fails with an error.

std::is_arithmetic< T >::value && ! std::is_same< T, bool >::value

Constant.

No-throw guarantee.

The converted number.

Name	Description
`ec`	Set to the error, if any occurred.