Interprocess communication (IPC) on the IBM® i operating system is made up of five services divided into the two categories of identifier-based services and pointer-based services. The identifier-based IPC services consist of message queues, semaphore sets, and shared memory. The pointer-based services consist of unnamed and named semaphores. The basic purpose of these services is to provide IBM i processes and threads with a way to communicate with each other through a set of standard APIs. These functions are based on the definitions in the Single UNIX® Specification.
The interprocess communication APIs are divided into the following categories:
Note: These functions use header (include) files from the library QSYSINC, which is optionally installable. Make sure QSYSINC is installed on your system before using any of the functions. See Header Files for UNIX-Type Functions for the file and member name of each header file.