1<!--$Id: set_func_yield.so,v 10.21 2007/10/24 20:06:08 bostic Exp $--> 2<!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> 3<!--See the file LICENSE for redistribution information.--> 4<html> 5<head> 6<title>Berkeley DB: db_env_set_func_yield</title> 7<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> 8<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> 9</head> 10<body bgcolor=white> 11<table width="100%"><tr valign=top> 12<td> 13<b>db_env_set_func_yield</b> 14</td> 15<td align=right> 16<a href="../api_c/api_core.html"><img src="../images/api.gif" alt="API"></a> 17<a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a></td> 18</tr></table> 19<hr size=1 noshade> 20<tt> 21<b><pre> 22#include <db.h> 23<p> 24int 25db_env_set_func_yield(int (*func_yield)(u_long secs, u_long usecs)); 26</pre></b> 27<hr size=1 noshade> 28<b>Description: db_env_set_func_yield</b> 29<p>The Berkeley DB library requires the ability to yield the processor from the 30current thread of control to any other waiting threads of control.</p> 31<p>The <b>func_yield</b> function must be able to cause the rescheduling 32of all participants in the current Berkeley DB environment, whether threaded 33or not. It may be incorrect to supply a thread <b>yield</b> function 34if more than a single process is operating in the Berkeley DB environment. 35This is because many thread-yield functions will not allow other 36processes to run, and the contested lock may be held by another process, 37not by another thread.</p> 38<p>The db_env_set_func_yield method configures all operations performed by a process and 39all of its threads of control, not operations confined to a single 40database environment.</p> 41<p>Although the db_env_set_func_yield method may be called at any time during the life of 42the application, it should normally be called before making calls to the 43<a href="../api_c/env_class.html">db_env_create</a> or <a href="../api_c/db_class.html">db_create</a> methods.</p> 44<p>The db_env_set_func_yield method 45returns a non-zero error value on failure 46and 0 on success. 47</p> 48<b>Parameters</b> <br> 49 <b>func_yield</b><ul compact><li>The <b>func_yield</b> parameter is the function which yields the processor. 50<p>The <b>secs</b> parameter is the number of seconds to pause before the 51thread of control should run again, or 0.</p> 52<p>The <b>usecs</b> parameter is the number of microseconds to pause 53before the thread of control should run again, or 0.</p> 54<p>The <b>func_yield</b> function must return the value of <b>errno</b> on 55failure and 0 on success.</p></ul> 56<br> 57<br><b>See Also</b> 58<a href="../ref/program/runtime.html">Run-time configuration</a> 59</tt> 60<table width="100%"><tr><td><br></td><td align=right> 61<a href="../api_c/api_core.html"><img src="../images/api.gif" alt="API"></a><a href="../ref/toc.html"><img src="../images/ref.gif" alt="Ref"></a> 62</td></tr></table> 63<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 64</body> 65</html> 66
