Trigger action list API

Collaboration diagram for Trigger action list API:

Functions
enum lttng_action_status	lttng_action_list_add_action (struct lttng_action *action_list, struct lttng_action *action)
	Appends the trigger action action to the action list action_list.
struct lttng_action *	lttng_action_list_create (void)
	Creates an empty trigger action list.
const struct lttng_action *	lttng_action_list_get_at_index (const struct lttng_action *action_list, unsigned int index)
	Returns the trigger action of the trigger action list action_list at the index index.
enum lttng_action_status	lttng_action_list_get_count (const struct lttng_action *action_list, unsigned int *count)
	Sets *count to the number of trigger actions contained in the action list action_list.

Detailed Description

A trigger action list is an ordered sequence of trigger actions.

A trigger action list is an action itself: it has the type LTTNG_ACTION_TYPE_LIST.

When a trigger having an action list as its action fires, LTTng attempts to execute its contained actions, in order. Whether or not LTTng executes a contained action depends on its rate policy. An action list doesn't have a rate policy itself.

Create a trigger action list with lttng_action_list_create().

Add a trigger action to an action list with lttng_action_list_add_action().

Get a trigger action from an action list with lttng_action_list_get_count() and lttng_action_list_get_at_index().

Function Documentation

lttng_action_list_add_action()

enum lttng_action_status lttng_action_list_add_action ( struct lttng_action *  action_list, struct lttng_action *  action  )

extern

Appends the trigger action action to the action list action_list.

Parameters

[in]	action_list	Trigger action list to which to add the action action.
[in]	action	Trigger action to add to action_list (not moved).

Return values

LTTNG_ACTION_STATUS_OK	Success.
LTTNG_ACTION_STATUS_INVALID	Unsatisfied precondition.
LTTNG_ACTION_STATUS_ERROR	Memory error.

Precondition

• action_list is not NULL.
• action_list has the type LTTNG_ACTION_TYPE_LIST.
• action is not NULL.
• action doesn't recursively contain action_list (no reference cycle).

lttng_action_list_create()

struct lttng_action * lttng_action_list_create ( void  )

extern

Creates an empty trigger action list.

Returns

Trigger action with the type LTTNG_ACTION_TYPE_LIST on success, or NULL on error.

Destroy the returned trigger action with lttng_action_destroy().

lttng_action_list_get_at_index()

const struct lttng_action * lttng_action_list_get_at_index ( const struct lttng_action *  action_list, unsigned int  index  )

extern

Returns the trigger action of the trigger action list action_list at the index index.

Parameters

[in]	action_list	Trigger action list of which to get the action at the index index.
[in]	index	Index of the trigger action to get from action_list.

Returns

Trigger action of action_list at the index index, or NULL on error.

action_list owns the returned trigger action.

The returned trigger action remains valid as long as action_list exists.

Precondition

• action_list is not NULL.
• action_list has the type LTTNG_ACTION_TYPE_LIST.
• index is less than the number of trigger actions (as returned by lttng_action_list_get_count()) of action_list.

See also

lttng_action_list_get_count() – Get the number of trigger actions of an action list.

lttng_action_list_get_count()

enum lttng_action_status lttng_action_list_get_count ( const struct lttng_action *  action_list, unsigned int *  count  )

extern

Sets *count to the number of trigger actions contained in the action list action_list.

Parameters

[in]	action_list	Trigger action list of which to get the number of contained actions.
[out]	count	On success, this function sets *count to the number of trigger actions in action_list.

Return values

LTTNG_ACTION_STATUS_OK	Success.
LTTNG_ACTION_STATUS_INVALID	Unsatisfied precondition.

Precondition

• action_list is not NULL.
• action_list has the type LTTNG_ACTION_TYPE_LIST.
• count is not NULL.

See also

lttng_action_list_get_at_index() – Get a trigger action from an action list by index.