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

Return result with a reference to the underlying double

boost::system::result< double & >
try_as_double() noexcept;
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Return result with the underlying double

boost::system::result< double >
try_as_double() const noexcept;
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