Interprocess Communications in Linux®: The Nooks & Crannies

Chapter 8. Shared Memory

Introduction

Shared memory allows multiple processes to share virtual memory space. This is the fastest but not necessarily the easiest (synchronization-wise) way for processes to communicate with one another. In general, one process creates or allocates the shared memory segment. The size and access permissions for the segment are set when it is created. The process then attaches the shared segment, causing it to be mapped^[1] into its current data space. If needed, the creating process then initializes the shared memory. Once created, and if permissions permit, other processes can gain access to the shared memory segment ...