/* Gnome-Streamer * Copyright (C) <1999> Erik Walthinsen * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #ifndef __GST_EXAMPLE_H__ #define __GST_EXAMPLE_H__ #include #ifdef __cplusplus extern "C" { #endif /* __cplusplus */ /* This is the definition of the element's object structure. */ typedef struct _GstExample GstExample; /* The structure itself is derived from GstElement, as can be seen by the * fact that there's a complete instance of the GstElement structure at * the beginning of the object. This allows the element to be cast to * an Element or even an Object. */ struct _GstExample { GstElement element; /* We need to keep track of our pads, so we do so here. */ GstPad *sinkpad,*srcpad; /* We'll use this to decide whether to do anything to the data we get. */ gboolean active; }; /* The other half of the object is its class. The class also derives from * the same parent, though it must be the class structure this time. * Function pointers for polymophic methods and signals are placed in this * structure. */ typedef struct _GstExampleClass GstExampleClass; struct _GstExampleClass { GstElementClass parent_class; /* signals */ void (*asdf) (GstElement *element, GstExample *example); }; /* Five standard preprocessing macros are used in the Gtk+ object system. * The first uses the object's _get_type function to return the GtkType * of the object. */ #define GST_TYPE_EXAMPLE \ (gst_example_get_type()) /* The second is a checking cast to the correct type. If the object passed * is not the right type, a warning will be generated on stderr. */ #define GST_EXAMPLE(obj) \ (GTK_CHECK_CAST((obj),GST_TYPE_EXAMPLE,GstExample)) /* The third is a checking cast of the class instead of the object. */ #define GST_EXAMPLE_CLASS(klass) \ (GTK_CHECK_CLASS_CAST((klass),GST_TYPE_EXAMPLE,GstExample)) /* The last two simply check to see if the passed pointer is an object or * class of the correct type. */ #define GST_IS_EXAMPLE(obj) \ (GTK_CHECK_TYPE((obj),GST_TYPE_EXAMPLE)) #define GST_IS_EXAMPLE_CLASS(obj) \ (GTK_CHECK_CLASS_TYPE((klass),GST_TYPE_EXAMPLE)) /* This is the only prototype needed, because it is used in the above * GST_TYPE_EXAMPLE macro. */ GtkType gst_example_get_type(void); #ifdef __cplusplus } #endif /* __cplusplus */ #endif /* __GST_EXAMPLE_H__ */