<!--$Id: set_func_yield.so,v 10.20 2004/08/13 03:39:02 bostic Exp $--> <!--Copyright (c) 1997,2007 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: db_env_set_func_yield</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> </head> <body bgcolor=white> <table width="100%"><tr valign=top> <td> <h3>db_env_set_func_yield</h3> </td> <td align=right> <a href="../../db46-devel-4.6.21/api_c/api_core.html"><img src="../../db46-devel-4.6.21/images/api.gif" alt="API"></a> <a href="../../db46-devel-4.6.21/ref/toc.html"><img src="../../db46-devel-4.6.21/images/ref.gif" alt="Ref"></a></td> </tr></table> <hr size=1 noshade> <tt> <h3><pre> #include <db.h> <p> int db_env_set_func_yield(int (*func_yield)(void)); </pre></h3> <hr size=1 noshade> <h3>Description: db_env_set_func_yield</h3> <p>The Berkeley DB library requires the ability to yield the processor from the current thread of control to any other waiting threads of control.</p> <p>The <b>func_yield</b> function must be able to cause the rescheduling of all participants in the current Berkeley DB environment, whether threaded or not. It may be incorrect to supply a thread <b>yield</b> function if more than a single process is operating in the Berkeley DB environment. This is because many thread-yield functions will not allow other processes to run, and the contested lock may be held by another process, not by another thread.</p> <p>If no <b>func_yield</b> function is specified, or if the <b>yield</b> function returns an error, the function specified by the <a href="../../db46-devel-4.6.21/api_c/set_func_sleep.html">db_env_set_func_sleep</a> entry will be used instead or subsequently; that is, if no <b>yield</b> function is specified, or if it is possible for the <b>yield</b> function to fail, the <b>sleep</b> function <b>must</b> cause the processor to reschedule any waiting threads of control for execution.</p> <p>The db_env_set_func_yield method configures all operations performed by a process and all of its threads of control, not operations confined to a single database environment.</p> <p>Although the db_env_set_func_yield method may be called at any time during the life of the application, it should normally be called before making calls to the <a href="../../db46-devel-4.6.21/api_c/env_class.html">db_env_create</a> or <a href="../../db46-devel-4.6.21/api_c/db_class.html">db_create</a> methods.</p> <p>The db_env_set_func_yield method returns a non-zero error value on failure and 0 on success. </p> <h3>Parameters</h3> <dl compact> <dt><b>func_yield</b><dd>The <b>func_yield</b> parameter is the function which yields the processor. <p>The <b>func_yield</b> function must return the value of <b>errno</b> on failure and 0 on success.</p> </dl> <h3>See Also</h3> <a href="../../db46-devel-4.6.21/ref/program/runtime.html">Run-time configuration</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../../db46-devel-4.6.21/api_c/api_core.html"><img src="../../db46-devel-4.6.21/images/api.gif" alt="API"></a><a href="../../db46-devel-4.6.21/ref/toc.html"><img src="../../db46-devel-4.6.21/images/ref.gif" alt="Ref"></a> </td></tr></table> <p><font size=1>Copyright (c) 1996,2007 Oracle. All rights reserved.</font> </body> </html>