<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >How can I use the doubly linked lists?</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="GTK+ FAQ" HREF="book1.html"><LINK REL="UP" TITLE="About GLib" HREF="c866.html"><LINK REL="PREVIOUS" TITLE="About GLib" HREF="c866.html"><LINK REL="NEXT" TITLE="Memory does not seem to be released when I free the list nodes I've allocated" HREF="x892.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" >GTK+ FAQ</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="c866.html" ACCESSKEY="P" ><<< Previous</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >About GLib</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="x892.html" ACCESSKEY="N" >Next >>></A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="AEN885" >How can I use the doubly linked lists?</A ></H1 ><P >The GList object is defined as:</P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><PRE CLASS="PROGRAMLISTING" >typedef struct _GList GList; struct _GList { gpointer data; GList *next; GList *prev; };</PRE ></TD ></TR ></TABLE ><P >To use the GList objects, simply:</P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><PRE CLASS="PROGRAMLISTING" >GList *list = NULL; GList *listrunner; gint array[] = { 1, 2, 3, 4, 5, 6 }; gint pos; gint *value; /* add data to the list */ for (pos=0;pos < sizeof array; pos++) { list = g_list_append(list, (gpointer)&array[pos]); } /* run through the list */ listrunner = g_list_first(list); while (listrunner) { value = (gint *)listrunner->data; printf("%d\n", *value); listrunner = g_list_next(listrunner); } /* removing datas from the list */ listrunner = g_list_first(list); list = g_list_remove_link(list, listrunner); list = g_list_remove(list, &array[4]);</PRE ></TD ></TR ></TABLE ><P >The same code is usable with singly linked lists (GSList objects) by replacing g_list_* functions with the relevant g_slist_* ones (g_slist_append, g_slist_remove, ...). Just remember that since you can't go backward in a singly linked list, there is no g_slist_first function - you'll need to keep a reference on the first node of the list.</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="c866.html" ACCESSKEY="P" ><<< Previous</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="book1.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="x892.html" ACCESSKEY="N" >Next >>></A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >About GLib</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="c866.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Memory does not seem to be released when I free the list nodes I've allocated</TD ></TR ></TABLE ></DIV ></BODY ></HTML >