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

This is the documentation for a snapshot of the develop branch, built from commit 3e299386d9.

Returns whether this object contains actual data or not.

bool
has_value() const;

Only returns true for default-constructed objects.

No-throw guarantee.

Constant.