<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <HTML ><HEAD ><TITLE >Constructor Functions</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="GStreamer Plugin Writer's Guide" HREF="index.html"><LINK REL="UP" TITLE="Constructing the Boilerplate" HREF="chapter-building-boiler.html"><LINK REL="PREVIOUS" TITLE="GstStaticPadTemplate" HREF="section-boiler-padtemplates.html"><LINK REL="NEXT" TITLE="The plugin_init function" HREF="section-boiler-plugininit.html"></HEAD ><BODY CLASS="sect1" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" ><SPAN CLASS="application" >GStreamer</SPAN > Plugin Writer's Guide</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="section-boiler-padtemplates.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 3. Constructing the Boilerplate</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="section-boiler-plugininit.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="sect1" ><H1 CLASS="sect1" ><A NAME="section-boiler-constructors" >3.6. Constructor Functions</A ></H1 ><P > Each element has three functions which are used for construction of an element. These are the <CODE CLASS="function" >_base_init()</CODE > function which is meant to initialize class and child class properties during each new child class creation; the <CODE CLASS="function" >_class_init()</CODE > function, which is used to initialise the class only once (specifying what signals, arguments and virtual functions the class has and setting up global state); and the <CODE CLASS="function" >_init()</CODE > function, which is used to initialise a specific instance of this type. </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="section-boiler-padtemplates.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="section-boiler-plugininit.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >GstStaticPadTemplate</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="chapter-building-boiler.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >The plugin_init function</TD ></TR ></TABLE ></DIV ></BODY ></HTML >