<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >I need to add a new signal to a GTK+ widget. Any idea?</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="Development with GTK+: general questions" HREF="c466.html"><LINK REL="PREVIOUS" TITLE="I have my signal connected to the the (whatever) event, but it seems I don't catch it. What's wrong?" HREF="x563.html"><LINK REL="NEXT" TITLE="Is it possible to get some text displayed which is truncated to fit inside its allocation?" HREF="x581.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="x563.html" ACCESSKEY="P" ><<< Previous</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Development with GTK+: general questions</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="x581.html" ACCESSKEY="N" >Next >>></A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="AEN571" >I need to add a new signal to a GTK+ widget. Any idea?</A ></H1 ><P >If the signal you want to add may be beneficial for other GTK+ users, you may want to submit a patch that presents your changes. Check the tutorial for more information about adding signals to a widget class.</P ><P >If you don't think it is the case or if your patch is not applied you'll have to use the <TT CLASS="LITERAL" >gtk_object_class_user_signal_new</TT > function. <TT CLASS="LITERAL" >gtk_object_class_user_signal_new</TT > allows you to add a new signal to a predefined GTK+ widget without any modification of the GTK+ source code. The new signal can be emited with <TT CLASS="LITERAL" >gtk_signal_emit</TT > and can be handled in the same way as other signals.</P ><P >Tim Janik posted this code snippet:</P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><PRE CLASS="PROGRAMLISTING" >static guint signal_user_action = 0; signal_user_action = gtk_object_class_user_signal_new (gtk_type_class (GTK_TYPE_WIDGET), "user_action", GTK_RUN_LAST | GTK_RUN_ACTION, gtk_marshal_NONE__POINTER, GTK_TYPE_NONE, 1, GTK_TYPE_POINTER); void gtk_widget_user_action (GtkWidget *widget, gpointer act_data) { g_return_if_fail (GTK_IS_WIDGET (widget)); gtk_signal_emit (GTK_OBJECT (widget), signal_user_action, act_data); }</PRE ></TD ></TR ></TABLE ><P >If you want your new signal to have more than the classical gpointer parameter, you'll have to play with GTK+ marshallers.</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="x563.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="x581.html" ACCESSKEY="N" >Next >>></A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >I have my signal connected to the the (whatever) event, but it seems I don't catch it. What's wrong?</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="c466.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Is it possible to get some text displayed which is truncated to fit inside its allocation?</TD ></TR ></TABLE ></DIV ></BODY ></HTML >