Free Trial

Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.


  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint
Share this Page URL
Help

45. Introduction to System V IPC > Algorithm Employed by System V IPC get Calls

Algorithm Employed by System V IPC get Calls

Figure 45-1 shows some of the structures used internally by the kernel to represent information about System V IPC objects (in this case semaphores, but the details are similar for other IPC mechanisms), including the fields used to calculate IPC keys. For each IPC mechanism (shared memory, message queue, or semaphore), the kernel maintains an associated ipc_ids structure that records various global information about all instances of that IPC mechanism. This information includes a dynamically sized array of pointers, entries, to the associated data structure for each object instance (semid_ds structures in the case of semaphores). The current size of the entries array is recorded in the size field, with the max_id field holding the index of the highest currently in-use element.


  

You are currently reading a PREVIEW of this book.

                                                                                                                    

Get instant access to over $1 million worth of books and videos.

  

Start a Free 10-Day Trial


  
  • Safari Books Online
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint