Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

value::as_double (1 of 2 overloads)

value::as_double (1 of 2 overloads)

Return a reference to the underlying double, or throw an exception.

Synopsis

double&
as_double(
    boost::source_location const& loc = BOOST_CURRENT_LOCATION);

Description

If is_double() is true, returns a reference to the underlying double, otherwise throws an exception.

Exception Safety

Strong guarantee.

Exceptions

Type	Thrown On
boost::system::system_error	`! this->is_double()`.

Parameters

Name	Description
`loc`	`source_location` to use in thrown exception; the source location of the call site by default.

Complexity

Constant.

Note

This function is intended for direct access to the underlying object, if it has the type double. It does not convert the underlying object to type double even if a lossless conversion is possible. If you are not sure which kind your value has, and you only care about getting a double number, consider using to_number instead.