The µOS++ port running on synthetic POSIX platforms is fully functional, except the scheduler runs in cooperative mode only; thread pre-emption might be possible, but was considered not worth the effort.
Context switching is implemented with makecontext(), getcontext(),
setcontext(), available on GNU/Linux and macOS.
The scheduler tick is implemented with setitimer(), which triggers a
periodic ITIMER_REAL signal.
For portability reasons, execution starts in the main() function.
Static constructors are executed before main(), as usual, but the order
is not known, so the code must not depend on any specific order.
In particular, registry classes must use the BSS memory initialisation to clear their data structures, and be sure the registry constructor does not clear them again, since at that moment it is possible that previous other classes to be registered.
The default trace output is STDOUT (MICRO_OS_PLUS_USE_TRACE_POSIX_STDOUT), but
can be redirected to STDERR by using MICRO_OS_PLUS_USE_TRACE_POSIX_STDERR.
The trace output is available from the very moment, in the first static constructor, since it does not need any initialisation.
The default memory allocator uses the system malloc().