Portable networking and other low-level I/O, including sockets, timers, hostname resolution, socket iostreams, serial ports, file descriptors and Windows HANDLEs.

C++11-style atomic types.

Parallel/GPU-computing library

(C++11) Context switching library.

Coroutine library.

(C++11) Coroutine library.

(C++11) Userland threads library.

Shared memory, memory mapped files, process-shared mutexes, condition variables, containers and allocators.

Lockfree data structures.

Message Passing Interface library, for use in distributed-memory parallel application programming.

Portable C++ multi-threading. C++11, C++14, C++17.