System V Inter-Process Communication Mechanisms

The HP-UX operating system uses shared memory to provide three mechanisms for communicating between cooperating programs and processes:

Messages: Message data is stored in a given part of shared memory to be retrieved by receiving programs. For more information about how shared memory space for messages is allocated and managed, see Overview of IPC Message Queue Operation.
Semaphores: Shared storage locations that contain up/down counters for signaling the current status of cooperating processes. For more information about how shared memory space for semaphores is allocated and managed, see Overview of IPC semaphore operation.
Shared Memory: Reserved data storage area shared by two or more processes by means of identically-defined data structures in each cooperating process. For more information about how shared memory space for shared data structures is allocated and managed, see Overview of IPC shared-memory operation.

Additional Information