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 2017. The current version is 1.89.0.
boost::process::extend::on_error — This handler is invoked if an error occured. The required signature is void(auto & exec, const std::error_code&), where Exec is a template parameter.
// In header: <boost/process/extend.hpp> unspecified on_error;