The OS/2 subsystem implements all OS/2 IPC mechanisms (semaphores, pipes, shared memory, queues, and signals).
The OS/2 subsystem implements named pipes on top of the Windows NT named pipe file system. These are supported transparently between Win32, MS-DOS, Win16, and OS/2 applications, both locally and remotely. Microsoft LAN Manager 2.x named pipe functionality is supported in its entirety.
Anonymous pipes, including inheritance, are fully supported. They are integrated into the OS/2 file handle space.
The full functionality of OS/2 1.x shared memory, including Get and Give semantics, is implemented using Windows NT shared memory features. The discardable segments property is ignored. (It is invisible to the OS/2 application).
The OS/2 subsystem supports the full range of OS/2 1.x semaphore APIs, including RAM semaphores in private and shared memory, system semaphores, and fast-safe RAM semaphores. Association of semaphores with timers and named pipes is fully supported. The OS/2 subsystem uses a combination of the Windows NT semaphore object and the Windows NT event object to implement an OS/2 semaphore.
OS/2 1.x queues are fully supported, using shared memory between OS/2 processes and OS/2 semaphores as required.
OS/2 signals are fully supported, using Windows NT APIs to manipulate thread context. The OS/2 subsystem controls the address space of OS/2 processes and uses it to manipulate the register content and the stack of thread 1 of the process to be signaled.