...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Shadow stack is part of Intel's Control-Flow Enforcement Technology. Users
must check if syscall 'map_shadow_stack' exists, which is no.451 and then
define SHADOW_STACK_SYSCALL
before including any Boost.Context headers if shadow stack protection is
enabled.