![]() | ![]() | ![]() | GNOME Library Reference Manual | ![]() |
---|
gnome-triggersgnome-triggers — Hierarchical signal mechanism for GNOME events. |
#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.
GTRIG_NONE | A null trigger type. Should never be used. |
GTRIG_FUNCTION | The trigger causes a function to be executed. |
GTRIG_COMMAND | The trigger causes a command to be executed (using execv() ).
|
GTRIG_MEDIAPLAY | The trigger causes a sound to be played. |
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 be
NULL .
|
level : | The severity level of the event. May be NULL .
|
supinfo : | The section in which the event belongs. This is a NULL terminated
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.
msg : | The human-readable message describing the event (can be NULL ).
|
level : | The level of severity of the event, or NULL .
|
... : | The classification of the event. |
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.
msg : | The human-readable message describing the event (can be NULL ).
|
level : | The level of severity of the event, or NULL .
|
supinfo : | The classification of the event (NULL terminated array).
|
<< gnome-sound | Lower level interactions >> |