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 an older version of Boost and was released in 2024. The current version is 1.89.0.

cancellation_filter::operator()

Returns type & Mask.

cancellation_type_t operator()(
    cancellation_type_t type) const;