POSIX Threads Programming. Table of Contents A thread is an independent, schedulable, stream of instructions. In the UNIX environment, a thread exists within a process, and uses the process resources. However, a thread possesses its own independent flow of control. There can be multiple threads within a process. Tasks which may be suitable for threading include tasks that: Block for potentially long waits Use many CPU cycles Must respond to asynchronous events Are of lesser or greater importance than other tasks Are able to be performed in parallel with other tasks A threaded program must possess reentrant functions/tasks. Example IBM Fortran Pthreads program The subroutines which comprise the Pthreads API can be informally grouped into three major classes: Thread management: The first class of functions work directly on threads - creating, detaching, joining, etc.
Example 1: This code fragment demostrates how to pass a simple integer to each thread. Dr. Dobb's | volatile - Multithreaded Programmer's Bes. POSIX Threads Programming. Table of Contents In shared memory multiprocessor architectures, such as SMPs, threads can be used to implement parallelism. Historically, hardware vendors have implemented their own proprietary versions of threads, making portability a concern for software developers. For UNIX systems, a standardized C language threads programming interface has been specified by the IEEE POSIX 1003.1c standard. Implementations that adhere to this standard are referred to as POSIX threads, or Pthreads. The tutorial begins with an introduction to concepts, motivations, and design considerations for using Pthreads.
Each of the three major classes of routines in the Pthreads API are then covered: Thread Management, Mutex Variables, and Condition Variables. Level/Prerequisites: This tutorial is one of the eight tutorials in the 4+ day "Using LLNL's Supercomputers" workshop. What is a Thread? What are Pthreads? Historically, hardware vendors have implemented their own proprietary versions of threads. Routines: S Guide to Network Programming. (Click here for other guides!) Hello, one and all! This is my little how-to guide on network programming using Internet sockets, or "sockets programming", for those of you who prefer it. The sockets API, though started by the Berkeley folk, has been ported to many many platforms, including Unix, Linux, and even Windows.
Unfortunately, it can be a little, um, "much" to digest the API, but as long as you know some C or C++, this guide should springboard you into the realm of network programming with hopefully as little hassle as humanly possible! What's Here for Readers: Errata (mistakes? What?) HTML:One section per page (read online) All on one page (read online) One section per page (tarball for download) One section per page (zipfile for download) All on one page (tarball for download) All on one page (zipfile for download) Mirrors: Let me know if you have mirrored the site. kfbk.net (Germany) tudelft.nl (Netherlands) retran.com (USA) Translations!
What's Here for Translators and Writers: Threads: Basic Theory and Librarie. Subsections This chapter examines aspects of threads and multiprocessing (and multithreading). We will firts study a little theory of threads and also look at how threading can be effectively used to make programs more efficient. The C thread libraries will then be introduced. The following chapters will look at further thead issues sucj a synchronisation and practical examples.
We can think of a thread as basically a lightweight process. Unit of resource ownership -- A process is allocated: a virtual address space to hold the process image control of some resources (files, I/O devices...) Unit of dispatching - A process is an execution path through one or more programs: execution may be interleaved with other processes the process has an execution state and a dispatching priority If we treat these two characteristics as being independent (as does modern OS theory): The unit of resource ownership is usually referred to as a process or task. Benefits of Threads vs Processes Single threading.