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 2020. The current version is 1.89.0.
#include <boost/exception/info.hpp>
typedef T value_type;
The expression error_info<Tag,T>::value_type evaluates to T.