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

object::try_at

Access the specified element, with bounds checking.

boost::system::result< value & >
try_at(
    string_view key) noexcept;
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boost::system::result< value const & >
try_at(
    string_view key) const noexcept;
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