Collaboration diagram for Event field value API:

Enumerations
enum	lttng_event_field_value_status { LTTNG_EVENT_FIELD_VALUE_STATUS_OK , LTTNG_EVENT_FIELD_VALUE_STATUS_INVALID , LTTNG_EVENT_FIELD_VALUE_STATUS_UNAVAILABLE }
	Return type of event field value API functions. More...

enum	lttng_event_field_value_type { LTTNG_EVENT_FIELD_VALUE_TYPE_UNSIGNED_INT , LTTNG_EVENT_FIELD_VALUE_TYPE_SIGNED_INT , LTTNG_EVENT_FIELD_VALUE_TYPE_UNSIGNED_ENUM , LTTNG_EVENT_FIELD_VALUE_TYPE_SIGNED_ENUM , LTTNG_EVENT_FIELD_VALUE_TYPE_REAL , LTTNG_EVENT_FIELD_VALUE_TYPE_STRING , LTTNG_EVENT_FIELD_VALUE_TYPE_ARRAY , LTTNG_EVENT_FIELD_VALUE_TYPE_BLOB , LTTNG_EVENT_FIELD_VALUE_TYPE_INVALID , LTTNG_EVENT_FIELD_VALUE_TYPE_UNKNOWN }
	Event field value type. More...

Functions
enum lttng_event_field_value_status	lttng_event_field_value_array_get_element_at_index (const struct lttng_event_field_value field_val, unsigned int index, const struct lttng_event_field_value *elem_field_val)
	Sets `*elem_field_val` to the element of the array event field value `field_val` at the index `index`.

enum lttng_event_field_value_status	lttng_event_field_value_array_get_length (const struct lttng_event_field_value field_val, unsigned int length)
	Sets `*length` to the length of the array event field value `field_val`.

enum lttng_event_field_value_status	lttng_event_field_value_blob_get_data (const struct lttng_event_field_value field_val, const uint8_t *data)
	Sets `*data` to the data pointer of the BLOB event field value `field_val`.

enum lttng_event_field_value_status	lttng_event_field_value_blob_get_length (const struct lttng_event_field_value field_val, size_t length)
	Sets `*length` to the length (byte count) of the BLOB event field value `field_val`.

enum lttng_event_field_value_status	lttng_event_field_value_blob_get_media_type (const struct lttng_event_field_value field_val, const char *media_type)
	Sets `*media_type` to the IANA media type of the BLOB event field value `field_val`.

enum lttng_event_field_value_type	lttng_event_field_value_get_type (const struct lttng_event_field_value *field_val)
	Returns the type of the event field value `field_val`.

enum lttng_event_field_value_status	lttng_event_field_value_real_get_value (const struct lttng_event_field_value field_val, double val)
	Sets `*val` to the raw value of the real number event field value `field_val`.

enum lttng_event_field_value_status	lttng_event_field_value_signed_int_get_value (const struct lttng_event_field_value field_val, int64_t val)
	Sets `*val` to the raw value of the signed integer event field value `field_val`.

enum lttng_event_field_value_status	lttng_event_field_value_string_get_value (const struct lttng_event_field_value field_val, const char *val)
	Sets `*val` to the raw value of the string event field value `field_val`.

enum lttng_event_field_value_status	lttng_event_field_value_unsigned_int_get_value (const struct lttng_event_field_value field_val, uint64_t val)
	Sets `*val` to the raw value of the unsigned integer event field value `field_val`.

Detailed Description

An event field value is the payload or context value of an event field.

See Event rule API to learn more about LTTng events.

When you create an “event rule matches” trigger condition, you may append capture descriptors with lttng_condition_event_rule_matches_append_capture_descriptor().

Then, when a trigger with such an “event rule matches” condition fires, the captured event field values are available through lttng_evaluation_event_rule_matches_get_captured_values().

Get the type of an event field value with lttng_event_field_value_get_type().

The available event field value types are:

Event field value type	Type enumerator(s)	Accessors
Unsigned integer/enumeration	LTTNG_EVENT_FIELD_VALUE_TYPE_UNSIGNED_INT and LTTNG_EVENT_FIELD_VALUE_TYPE_UNSIGNED_ENUM	lttng_event_field_value_unsigned_int_get_value()
Signed integer/enumeration	LTTNG_EVENT_FIELD_VALUE_TYPE_SIGNED_INT and LTTNG_EVENT_FIELD_VALUE_TYPE_SIGNED_ENUM	lttng_event_field_value_signed_int_get_value()
Real number	LTTNG_EVENT_FIELD_VALUE_TYPE_REAL	lttng_event_field_value_real_get_value()
String	LTTNG_EVENT_FIELD_VALUE_TYPE_STRING	lttng_event_field_value_string_get_value()
BLOB (binary large object)	LTTNG_EVENT_FIELD_VALUE_TYPE_BLOB	lttng_event_field_value_blob_get_media_type(), lttng_event_field_value_blob_get_length(), and lttng_event_field_value_blob_get_data()
Array	LTTNG_EVENT_FIELD_VALUE_TYPE_ARRAY	lttng_event_field_value_array_get_length() and lttng_event_field_value_array_get_element_at_index()

Enumeration Type Documentation

◆ lttng_event_field_value_status

enum lttng_event_field_value_status

Return type of event field value API functions.

Enumerator
LTTNG_EVENT_FIELD_VALUE_STATUS_OK	Success.
LTTNG_EVENT_FIELD_VALUE_STATUS_INVALID	Unsatisfied precondition.
LTTNG_EVENT_FIELD_VALUE_STATUS_UNAVAILABLE	Event field value is not available.

◆ lttng_event_field_value_type

enum lttng_event_field_value_type

Event field value type.

Get the type of an event field value with lttng_event_field_value_get_type().

Enumerator
LTTNG_EVENT_FIELD_VALUE_TYPE_UNSIGNED_INT	Unsigned integer.
LTTNG_EVENT_FIELD_VALUE_TYPE_SIGNED_INT	Signed integer.
LTTNG_EVENT_FIELD_VALUE_TYPE_UNSIGNED_ENUM	Unsigned enumeration. Conceptually inherits LTTNG_EVENT_FIELD_VALUE_TYPE_UNSIGNED_INT.
LTTNG_EVENT_FIELD_VALUE_TYPE_SIGNED_ENUM	Signed enumeration. Conceptually inherits LTTNG_EVENT_FIELD_VALUE_TYPE_SIGNED_INT.
LTTNG_EVENT_FIELD_VALUE_TYPE_REAL	Real number.
LTTNG_EVENT_FIELD_VALUE_TYPE_STRING	String.
LTTNG_EVENT_FIELD_VALUE_TYPE_ARRAY	Array.
LTTNG_EVENT_FIELD_VALUE_TYPE_BLOB	BLOB (binary large object).
LTTNG_EVENT_FIELD_VALUE_TYPE_INVALID	Unsatisfied precondition.
LTTNG_EVENT_FIELD_VALUE_TYPE_UNKNOWN	Unknown (error).

Function Documentation

◆ lttng_event_field_value_array_get_element_at_index()

enum lttng_event_field_value_status lttng_event_field_value_array_get_element_at_index	(	const struct lttng_event_field_value *	field_val,
		unsigned int	index,
		const struct lttng_event_field_value **	elem_field_val
	)

extern

Sets *elem_field_val to the element of the array event field value field_val at the index index.

It's possible that field_val doesn't actually have any element at the index index, in which case this function returns LTTNG_EVENT_FIELD_VALUE_STATUS_UNAVAILABLE.

Parameters

[in] field_val Array event field value of which to get the element at the index index.

[in] index Index of the element to get from field_val.

[out]

elem_field_val

On success, this function sets *elem_field_val to the element of field_val at the index index.

field_val owns *elem_field_val.

*elem_field_val remains valid until the next function call with field_val.

Return values

LTTNG_EVENT_FIELD_VALUE_STATUS_OK	Success.
LTTNG_EVENT_FIELD_VALUE_STATUS_INVALID	Unsatisfied precondition.
LTTNG_EVENT_FIELD_VALUE_STATUS_UNAVAILABLE	The element of `field_val` at the index `index` is not available.

Precondition

field_val is not NULL.
field_val has the type LTTNG_EVENT_FIELD_VALUE_TYPE_ARRAY.
index is less than the number of elements of field_val (as given by lttng_event_field_value_array_get_length()).
elem_field_val is not NULL.

See also: lttng_event_field_value_array_get_length() – Get the length of an array event field value.

◆ lttng_event_field_value_array_get_length()

enum lttng_event_field_value_status lttng_event_field_value_array_get_length	(	const struct lttng_event_field_value *	field_val,
		unsigned int *	length
	)

extern

Sets *length to the length of the array event field value field_val.

Parameters

[in]	field_val	Array event field value of which to get the length.
[out]	length	On success, this function sets `*length` to the length of `field_val`.

Return values

LTTNG_EVENT_FIELD_VALUE_STATUS_OK	Success.
LTTNG_EVENT_FIELD_VALUE_STATUS_INVALID	Unsatisfied precondition.

Precondition

field_val is not NULL.
field_val has the type LTTNG_EVENT_FIELD_VALUE_TYPE_ARRAY.
length is not NULL.

See also: lttng_event_field_value_array_get_element_at_index() – Get an element of a an array event field value by index.

◆ lttng_event_field_value_blob_get_data()

enum lttng_event_field_value_status lttng_event_field_value_blob_get_data	(	const struct lttng_event_field_value *	field_val,
		const uint8_t **	data
	)

extern

Sets *data to the data pointer of the BLOB event field value field_val.

Parameters

[in] field_val BLOB event field value of which to get the data pointer.

[out]

data

On success, this function sets *data to the data pointer of field_val.

The length of *data is what lttng_event_field_value_blob_get_length() returns with field_val.

field_val owns *data.

*data remains valid until the next function call with field_val.

Return values

LTTNG_EVENT_FIELD_VALUE_STATUS_OK	Success.
LTTNG_EVENT_FIELD_VALUE_STATUS_INVALID	Unsatisfied precondition.

Precondition

field_val is not NULL.
field_val has the type LTTNG_EVENT_FIELD_VALUE_TYPE_BLOB.
data is not NULL.

See also: lttng_event_field_value_blob_get_length() – Get the length of a BLOB event field value.

◆ lttng_event_field_value_blob_get_length()

enum lttng_event_field_value_status lttng_event_field_value_blob_get_length	(	const struct lttng_event_field_value *	field_val,
		size_t *	length
	)

extern

Sets *length to the length (byte count) of the BLOB event field value field_val.

Parameters

[in]	field_val	BLOB event field value of which to get the length.
[out]	length	On success, this function sets `*length` to the length of `field_val`.

Return values

LTTNG_EVENT_FIELD_VALUE_STATUS_OK	Success.
LTTNG_EVENT_FIELD_VALUE_STATUS_INVALID	Unsatisfied precondition.

Precondition

field_val is not NULL.
field_val has the type LTTNG_EVENT_FIELD_VALUE_TYPE_BLOB.
length is not NULL.

See also: lttng_event_field_value_blob_get_data() – Get the data pointer of a BLOB event field value.

◆ lttng_event_field_value_blob_get_media_type()

enum lttng_event_field_value_status lttng_event_field_value_blob_get_media_type	(	const struct lttng_event_field_value *	field_val,
		const char **	media_type
	)

extern

Sets *media_type to the IANA media type of the BLOB event field value field_val.

Parameters

[in] field_val BLOB event field value of which to get the IANA media type.

[out]

media_type

On success, this function sets *media_type to the IANA media type of field_val.

field_val owns *media_type.

*media_type remains valid until the next function call with field_val.

Return values

LTTNG_EVENT_FIELD_VALUE_STATUS_OK	Success.
LTTNG_EVENT_FIELD_VALUE_STATUS_INVALID	Unsatisfied precondition.

Precondition

field_val is not NULL.
field_val has the type LTTNG_EVENT_FIELD_VALUE_TYPE_BLOB.
media_type is not NULL.

◆ lttng_event_field_value_get_type()

enum lttng_event_field_value_type lttng_event_field_value_get_type ( const struct lttng_event_field_value * field_val )

extern

Returns the type of the event field value field_val.

Parameters

[in] field_val Event field value of which to get the type.

Returns: Type of field_val.

Precondition

field_val is not NULL.

◆ lttng_event_field_value_real_get_value()

enum lttng_event_field_value_status lttng_event_field_value_real_get_value	(	const struct lttng_event_field_value *	field_val,
		double *	val
	)

extern

Sets *val to the raw value of the real number event field value field_val.

Parameters

[in]	field_val	Real number event field value of which to get the raw value.
[out]	val	On success, this function sets `*val` to the raw value of `field_val`.

Return values

LTTNG_EVENT_FIELD_VALUE_STATUS_OK	Success.
LTTNG_EVENT_FIELD_VALUE_STATUS_INVALID	Unsatisfied precondition.

Precondition

field_val is not NULL.
field_val has the type LTTNG_EVENT_FIELD_VALUE_TYPE_REAL.
val is not NULL.

◆ lttng_event_field_value_signed_int_get_value()

enum lttng_event_field_value_status lttng_event_field_value_signed_int_get_value	(	const struct lttng_event_field_value *	field_val,
		int64_t *	val
	)

extern

Sets *val to the raw value of the signed integer event field value field_val.

Parameters

[in]	field_val	Signed integer event field value of which to get the raw value.
[out]	val	On success, this function sets `*val` to the raw value of `field_val`.

Return values

LTTNG_EVENT_FIELD_VALUE_STATUS_OK	Success.
LTTNG_EVENT_FIELD_VALUE_STATUS_INVALID	Unsatisfied precondition.

Precondition

field_val is not NULL.
field_val has the type LTTNG_EVENT_FIELD_VALUE_TYPE_SIGNED_INT or LTTNG_EVENT_FIELD_VALUE_TYPE_SIGNED_ENUM.
val is not NULL.

See also: lttng_event_field_value_unsigned_int_get_value() – Get the raw value of an unsigned integer event field value.

◆ lttng_event_field_value_string_get_value()

enum lttng_event_field_value_status lttng_event_field_value_string_get_value	(	const struct lttng_event_field_value *	field_val,
		const char **	val
	)

extern

Sets *val to the raw value of the string event field value field_val.

Parameters

[in] field_val String event field value of which to get the raw value.

[out]

val

On success, this function sets *val to the raw value of field_val.

field_val owns *val.

*val remains valid until the next function call with field_val.

Return values

LTTNG_EVENT_FIELD_VALUE_STATUS_OK	Success.
LTTNG_EVENT_FIELD_VALUE_STATUS_INVALID	Unsatisfied precondition.

Precondition

field_val is not NULL.
field_val has the type LTTNG_EVENT_FIELD_VALUE_TYPE_STRING.
val is not NULL.

◆ lttng_event_field_value_unsigned_int_get_value()

enum lttng_event_field_value_status lttng_event_field_value_unsigned_int_get_value	(	const struct lttng_event_field_value *	field_val,
		uint64_t *	val
	)

extern

Sets *val to the raw value of the unsigned integer event field value field_val.

Parameters

[in]	field_val	Unsigned integer event field value of which to get the raw value.
[out]	val	On success, this function sets `*val` to the raw value of `field_val`.

Return values

LTTNG_EVENT_FIELD_VALUE_STATUS_OK	Success.
LTTNG_EVENT_FIELD_VALUE_STATUS_INVALID	Unsatisfied precondition.

Precondition

field_val is not NULL.
field_val has the type LTTNG_EVENT_FIELD_VALUE_TYPE_UNSIGNED_INT or LTTNG_EVENT_FIELD_VALUE_TYPE_UNSIGNED_ENUM.
val is not NULL.

See also: lttng_event_field_value_signed_int_get_value() – Get the raw value of a signed integer event field value.

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ lttng_event_field_value_status

◆ lttng_event_field_value_type

Function Documentation

◆ lttng_event_field_value_array_get_element_at_index()

◆ lttng_event_field_value_array_get_length()

◆ lttng_event_field_value_blob_get_data()

◆ lttng_event_field_value_blob_get_length()

◆ lttng_event_field_value_blob_get_media_type()

◆ lttng_event_field_value_get_type()

◆ lttng_event_field_value_real_get_value()

◆ lttng_event_field_value_signed_int_get_value()

◆ lttng_event_field_value_string_get_value()

◆ lttng_event_field_value_unsigned_int_get_value()