value::try_as_double
Return result with a reference to the underlying double
Synopsis
boost::system::result< double & >
try_as_double() noexcept; (1)
boost::system::result< double >
try_as_double() const noexcept; (2)Description
If is_double() is true, the result contains a reference to the underlying double, otherwise it contains an error_code.
Example
The return value can be used in both a boolean context and to assign a variable:
if( auto r = jv.try_as_double() )
return *r;But can also be used to throw an exception on error:
return jv.try_as_double().value();Complexity
Constant.
Exception Safety
No-throw guarantee.