Summary
Message queues are one of three interprocess communication facilities added to UNIX with the release of System V. Once created, a message queue is maintained by the system. Unrelated processes, executing at different times, can use a message queue to pass information. Each message has an associated type that can be used to implement a rudimentary form of data multiplexing when multiple producers are involved. Message queues are created and accessed using the msgget system call. Messages are placed in the message queue with the msgsnd system call and retrieved from the queue with the msgrcv system call. Additional message queue manipulations are carried out with the msgctl system call. The msgctl system call returns information about the message queue, permits modification of access permissions, and allows the owner to remove the message queue facility.
Programs and Processes
- Introduction
- Library Functions
- System Calls
- Linking Object Code
- Managing Failures
- Executable File Format
- System Memory
- Process Memory
- The u Area
- Process Memory Addresses
- Creating a Process
- Summary
- Key Terms and Concepts
Processing Environment
- Introduction
- Process ID
- Parent Process ID
- Process Group ID
- Permissions
- Real and Effective User and Group IDs
- File System Information
- File Information
- Process Resource Limits
- Signaling Processes
- Command-Line Values
- Environment Variables
- The /proc Filesystem
- Summary
- Key Terms and Concepts
Using Processes
- Introduction
- The fork System Call Revisited
- exec s Minions
- Using fork and exec Together
- Ending a Process
- Waiting on Processes
- Summary
- Key Terms and Concepts
Primitive Communications
- Introduction
- Lock Files
- Locking Files
- More About Signals
- Signal and Signal Management Calls
- Summary
- Key Terms and Concepts
Pipes
Message Queues
- Introduction
- IPC System Calls: A Synopsis
- Creating a Message Queue
- Message Queue Control
- Message Queue Operations
- A ClientServer Message Queue Example
- Message Queue Class
- Summary
- Key Terms and Concepts
Semaphores
- Introduction
- Creating and Accessing Semaphore Sets
- Semaphore Control
- Semaphore Operations
- Semaphore Class
- Summary
- Key Terms and Concepts
Shared Memory
- Introduction
- Creating a Shared Memory Segment
- Shared Memory Control
- Shared Memory Operations
- Using a File as Shared Memory
- Shared Memory Class
- Summary
- Key Terms and Concepts
Remote Procedure Calls
- Introduction
- Executing Remote Commands at a System Level
- Executing Remote Commands in a Program
- Transforming a Local Function Call into a Remote Procedure
- Debugging RPC Applications
- Using RPCGEN to Generate Templates and a MAKEFILE
- Encoding and Decoding Arbitrary Data Types
- Using Broadcasting to Search for an RPC Service
- Summary
- Key Terms and Concepts
Sockets
- Introduction
- Communication Basics
- IPC Using Socketpair
- Sockets: The Connection-Oriented Paradigm
- Sockets: The Connectionless Paradigm
- Multiplexing I/O with select
- Peeking at Data
- Out of Band Messages
- Summary
- Key Terms and Concepts
Threads
- Introduction
- Creating a Thread
- Exiting a Thread
- Basic Thread Management
- Thread Attributes
- Scheduling Threads
- Using Signals in Threads
- Thread Synchronization
- Thread-Specific Data
- Debugging Multithreaded Programs
- Summary
- Nomenclature and Key Concepts
Appendix A. Using Linux Manual Pages
Appendix B. UNIX Error Messages
Appendix C. RPC Syntax Diagrams
Appendix D. Profiling Programs
EAN: 2147483647
Pages: 136
