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#include <libgnome/libgnome.h> enum GnomeTriggerType; void (*GnomeTriggerActionFunction) (char *msg, char *level, char *supinfo[]); GnomeTrigger; void gnome_triggers_add_trigger (GnomeTrigger *nt, ...); void gnome_triggers_vadd_trigger (GnomeTrigger *nt, char *supinfo[]); void gnome_triggers_do (const char *msg, const char *level, ...); void gnome_triggers_vdo (const char *msg, const char *level, const char *supinfo[]);
The triggers API provides a way for applications to tell GNOME about interesting events that then cause something to happen (for example, playing a sound). An event can either be a function that is called, a sound that is played or an external command that is run.
Each trigger can optionally have a level associated with it and a section. The section is a list of strings that help to classify the event, which imposes a hierarchy on the trigger system. For example, messages about the hard drive partition /dev/hda1 may come under the section ("system", "device", "disk", "/dev/hda1"). This means that an application could trigger all events for the ("system", "device") sections and include those events, or be more specific and just trigger those for ("system", "device", "disk", "/dev/hda1").
At the present time, triggers are not widely used in GNOME, being mostly used to play sound events in response to certain actions.
typedef enum {
	GTRIG_NONE,
	GTRIG_FUNCTION,
	GTRIG_COMMAND,
	GTRIG_MEDIAPLAY
} GnomeTriggerType;
These are the different types of triggers that can be activated by an application.
void        (*GnomeTriggerActionFunction)   (char *msg,
                                             char *level,
                                             char *supinfo[]);
The signature of a function that can used as a target for GTRIG_FUNCTION types of GnomeTrigger instances.
| msg: | The human-readable message that was passed to gnome_triggers_do(). May beNULL. | 
| level: | The severity level of the event. May be NULL. | 
| supinfo: | The section in which the event belongs. This is a NULLterminated
array. | 
typedef struct {
	GnomeTriggerType type;
	union {
		/*
		 * These will be passed the same info as
		 * gnome_triggers_do was given.
		 */
		GnomeTriggerActionFunction function;
		gchar *command;
		struct {
			gchar *file;
			int cache_id;
		} media;
	} u;
        gchar *level;
} GnomeTrigger;
This structure stores the information about an action that is triggered for
a particular event. A filled in instance of this structure is passed to
gnome_triggers_add_trigger() and gnome_triggers_vadd_trigger().
void gnome_triggers_add_trigger (GnomeTrigger *nt, ...);
Adds a new GnomeTrigger instance to the event hierarchy.
| nt: | Information on the new trigger to be added. | 
| ...: | The section to add the trigger under. | 
void gnome_triggers_vadd_trigger (GnomeTrigger *nt, char *supinfo[]);
This does the same as gnome_triggers_add_trigger(), except the section is
stored in the NULL terminated array supinfo instead of as a variable
length argument list.
| nt: | Information on the new trigger to be added. | 
| supinfo: | The section to add the trigger under. | 
void        gnome_triggers_do               (const char *msg,
                                             const char *level,
                                             ...);
Notifies GNOME about an event happening, so that any appropriate handlers can be run.
void        gnome_triggers_vdo              (const char *msg,
                                             const char *level,
                                             const char *supinfo[]);
Notifies GNOME about an event happening, so that any appropriate handlers
can be run. This does the same as gnome_trigger_do() except that it takes a
NULL terminated array instead of a varargs list.