<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html lang="en-us" xml:lang="en-us"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="security" content="public" /> <meta name="Robots" content="index,follow" /> <meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' /> <meta name="DC.Type" content="concept" /> <meta name="DC.Title" content="Thread safety" /> <meta name="abstract" content="A function is considered threadsafe if you can start it simultaneously in multiple threads within the same process." /> <meta name="description" content="A function is considered threadsafe if you can start it simultaneously in multiple threads within the same process." /> <meta name="DC.Relation" scheme="URI" content="aconcepts.htm" /> <meta name="DC.Relation" scheme="URI" content="xthread.htm" /> <meta name="DC.Relation" scheme="URI" content="xdns.htm" /> <meta name="copyright" content="(C) Copyright IBM Corporation 2001, 2006" /> <meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2001, 2006" /> <meta name="DC.Format" content="XHTML" /> <meta name="DC.Identifier" content="cthread" /> <meta name="DC.Language" content="en-us" /> <!-- All rights reserved. Licensed Materials Property of IBM --> <!-- US Government Users Restricted Rights --> <!-- Use, duplication or disclosure restricted by --> <!-- GSA ADP Schedule Contract with IBM Corp. --> <link rel="stylesheet" type="text/css" href="./ibmdita.css" /> <link rel="stylesheet" type="text/css" href="./ic.css" /> <title>Thread safety</title> </head> <body id="cthread"><a name="cthread"><!-- --></a> <!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script> <h1 class="topictitle1">Thread safety</h1> <div><p>A function is considered threadsafe if you can start it simultaneously in multiple threads within the same process.</p> <p>A function is threadsafe if and only if all the functions it calls are threadsafe also. Socket APIs are comprised of system and network functions, which are both threadsafe.</p> <p>All network functions with names that end in "_r" have similar semantics and are also threadsafe. </p> <p>The other resolver routines are threadsafe with each other but they use the _res data structure. This data structure is shared between all threads in a process and can be changed by an application during a resolver call. </p> </div> <div> <div class="familylinks"> <div class="parentlink"><strong>Parent topic:</strong> <a href="aconcepts.htm" title="Advanced socket concepts go beyond a general discussion of what sockets are and how they work. They provide ways to design socket applications for larger and more complex networks.">Advanced socket concepts</a></div> </div> <div class="relref"><strong>Related reference</strong><br /> <div><a href="xthread.htm" title="Here is an example of a program that uses gethostbyaddr_r().">Example: Use gethostbyaddr_r() for threadsafe network routines</a></div> <div><a href="xdns.htm" title="This example shows how to query and update Domain Name System (DNS) records.">Example: Update and query DNS</a></div> </div> </div> </body> </html>