# LV2

An open and extensible audio plugin standard

Version | 1.18.10

Topics | Data Structures | Macros | Typedefs
Atom
LV2

## Detailed Description

A generic value container and several data types.

See http://lv2plug.in/ns/ext/atom for details.

## Topics
| Forge
| Utilities

## Data Structures
struct | LV2_Atom
struct | LV2_Atom_Int
struct | LV2_Atom_Long
struct | LV2_Atom_Float
struct | LV2_Atom_Double
struct | LV2_Atom_URID
struct | LV2_Atom_String
struct | LV2_Atom_Literal_Body
struct | LV2_Atom_Literal
struct | LV2_Atom_Tuple
struct | LV2_Atom_Vector_Body
struct | LV2_Atom_Vector
struct | LV2_Atom_Property_Body
struct | LV2_Atom_Property
struct | LV2_Atom_Object_Body
struct | LV2_Atom_Object
struct | LV2_Atom_Event
struct | LV2_Atom_Sequence_Body
struct | LV2_Atom_Sequence
union | LV2_Atom_Event.time

## Macros
#define | LV2_ATOM_URI "http://lv2plug.in/ns/ext/atom"
#define | LV2_ATOM_PREFIX LV2_ATOM_URI "#"
#define | LV2_ATOM__Atom LV2_ATOM_PREFIX "Atom"
#define | LV2_ATOM__AtomPort LV2_ATOM_PREFIX "AtomPort"
#define | LV2_ATOM__Blank LV2_ATOM_PREFIX "Blank"
#define | LV2_ATOM__Bool LV2_ATOM_PREFIX "Bool"
#define | LV2_ATOM__Chunk LV2_ATOM_PREFIX "Chunk"
#define | LV2_ATOM__Double LV2_ATOM_PREFIX "Double"
#define | LV2_ATOM__Event LV2_ATOM_PREFIX "Event"
#define | LV2_ATOM__Float LV2_ATOM_PREFIX "Float"
#define | LV2_ATOM__Int LV2_ATOM_PREFIX "Int"
#define | LV2_ATOM__Literal LV2_ATOM_PREFIX "Literal"
#define | LV2_ATOM__Long LV2_ATOM_PREFIX "Long"
#define | LV2_ATOM__Number LV2_ATOM_PREFIX "Number"
#define | LV2_ATOM__Object LV2_ATOM_PREFIX "Object"
#define | LV2_ATOM__Path LV2_ATOM_PREFIX "Path"
#define | LV2_ATOM__Property LV2_ATOM_PREFIX "Property"
#define | LV2_ATOM__Resource LV2_ATOM_PREFIX "Resource"
#define | LV2_ATOM__Sequence LV2_ATOM_PREFIX "Sequence"
#define | LV2_ATOM__Sound LV2_ATOM_PREFIX "Sound"
#define | LV2_ATOM__String LV2_ATOM_PREFIX "String"
#define | LV2_ATOM__Tuple LV2_ATOM_PREFIX "Tuple"
#define | LV2_ATOM__URI LV2_ATOM_PREFIX "URI"
#define | LV2_ATOM__URID LV2_ATOM_PREFIX "URID"
#define | LV2_ATOM__Vector LV2_ATOM_PREFIX "Vector"
#define | LV2_ATOM__atomTransfer LV2_ATOM_PREFIX "atomTransfer"
#define | LV2_ATOM__beatTime LV2_ATOM_PREFIX "beatTime"
#define | LV2_ATOM__bufferType LV2_ATOM_PREFIX "bufferType"
#define | LV2_ATOM__childType LV2_ATOM_PREFIX "childType"
#define | LV2_ATOM__eventTransfer LV2_ATOM_PREFIX "eventTransfer"
#define | LV2_ATOM__frameTime LV2_ATOM_PREFIX "frameTime"
#define | LV2_ATOM__supports LV2_ATOM_PREFIX "supports"
#define | LV2_ATOM__timeUnit LV2_ATOM_PREFIX "timeUnit"
#define | LV2_ATOM_REFERENCE_TYPE 0
#define | LV2_ATOM_CONTENTS(type, atom)
#define | LV2_ATOM_CONTENTS_CONST(type, atom)
#define | LV2_ATOM_BODY(atom)
#define | LV2_ATOM_BODY_CONST(atom)

## Typedefs
typedef LV2_Atom_Int | LV2_Atom_Bool

## Data Structure Documentation

## ◆ LV2_Atom

struct LV2_Atom

The header of an atom:Atom.

Data Fields
uint32_t | size | Size in bytes, not including type and size.
uint32_t | type | Type of this atom (mapped URI).

## ◆ LV2_Atom_Int

struct LV2_Atom_Int

An atom:Int or atom:Bool.

May be cast to LV2_Atom.

Data Fields
LV2_Atom | atom | Atom header.
int32_t | body | Integer value.

## ◆ LV2_Atom_Long

struct LV2_Atom_Long

An atom:Long.

May be cast to LV2_Atom.

Data Fields
LV2_Atom | atom | Atom header.
int64_t | body | Integer value.

## ◆ LV2_Atom_Float

struct LV2_Atom_Float

An atom:Float.

May be cast to LV2_Atom.

Data Fields
LV2_Atom | atom | Atom header.
float | body | Floating point value.

## ◆ LV2_Atom_Double

struct LV2_Atom_Double

An atom:Double.

May be cast to LV2_Atom.

Data Fields
LV2_Atom | atom | Atom header.
double | body | Floating point value.

## ◆ LV2_Atom_URID

struct LV2_Atom_URID

An atom:URID.

May be cast to LV2_Atom.

Data Fields
LV2_Atom | atom | Atom header.
uint32_t | body | URID.

## ◆ LV2_Atom_String

struct LV2_Atom_String

An atom:String.

May be cast to LV2_Atom.

Data Fields
LV2_Atom | atom | Atom header.

## ◆ LV2_Atom_Literal_Body

struct LV2_Atom_Literal_Body

The body of an atom:Literal.

Data Fields
uint32_t | datatype | Datatype URID.
uint32_t | lang | Language URID.

## ◆ LV2_Atom_Literal

struct LV2_Atom_Literal

An atom:Literal.

May be cast to LV2_Atom.

Data Fields
LV2_Atom | atom | Atom header.
LV2_Atom_Literal_Body | body | Body.

## ◆ LV2_Atom_Tuple

struct LV2_Atom_Tuple

An atom:Tuple.

May be cast to LV2_Atom.

Data Fields
LV2_Atom | atom | Atom header.

## ◆ LV2_Atom_Vector_Body

struct LV2_Atom_Vector_Body

The body of an atom:Vector.

Data Fields
uint32_t | child_size | The size of each element in the vector.
uint32_t | child_type | The type of each element in the vector.

## ◆ LV2_Atom_Vector

struct LV2_Atom_Vector

An atom:Vector.

May be cast to LV2_Atom.

Data Fields
LV2_Atom | atom | Atom header.
LV2_Atom_Vector_Body | body | Body.

## ◆ LV2_Atom_Property_Body

struct LV2_Atom_Property_Body

The body of an atom:Property (typically in an atom:Object).

Data Fields
uint32_t | key | Key (predicate) (mapped URI).
uint32_t | context | Context URID (may be, and generally is, 0).
LV2_Atom | value | Value atom header.

## ◆ LV2_Atom_Property

struct LV2_Atom_Property

An atom:Property.

May be cast to LV2_Atom.

Data Fields
LV2_Atom | atom | Atom header.
LV2_Atom_Property_Body | body | Body.

## ◆ LV2_Atom_Object_Body

struct LV2_Atom_Object_Body

The body of an atom:Object.

May be cast to LV2_Atom.

Data Fields
uint32_t | id | URID, or 0 for blank.
uint32_t | otype | Type URID (same as rdf:type, for fast dispatch).

## ◆ LV2_Atom_Object

struct LV2_Atom_Object

An atom:Object.

May be cast to LV2_Atom.

Data Fields
LV2_Atom | atom | Atom header.
LV2_Atom_Object_Body | body | Body.

## ◆ LV2_Atom_Event

struct LV2_Atom_Event

The header of an atom:Event.

Note this type is NOT an LV2_Atom.

Data Fields
union LV2_Atom_Event.time | time | Time stamp. Which type is valid is determined by context.
LV2_Atom | body | Event body atom header.

## ◆ LV2_Atom_Sequence_Body

struct LV2_Atom_Sequence_Body

The body of an atom:Sequence (a sequence of events).

The unit field is either a URID that described an appropriate time stamp type, or may be 0 where a default stamp type is known. For LV2_Descriptor::run(), the default stamp type is audio frames.

The contents of a sequence is a series of LV2_Atom_Event, each aligned to 64-bits, for example:

    | Event 1 (size 6)                              | Event 2
    |       |       |       |       |       |       |       |       |
    | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
    |FRAMES         |TYPE   |SIZE   |DATADATADATAPAD|FRAMES         |...

Data Fields
uint32_t | unit | URID of unit of event time stamps.
uint32_t | pad | Currently unused.

## ◆ LV2_Atom_Sequence

struct LV2_Atom_Sequence

An atom:Sequence.

Data Fields
LV2_Atom | atom | Atom header.
LV2_Atom_Sequence_Body | body | Body.

## ◆ LV2_Atom_Event.time

union LV2_Atom_Event.time

Time stamp.

Which type is valid is determined by context.

Data Fields
int64_t | frames | Time in audio frames.
double | beats | Time in beats.

## Macro Definition Documentation

## ◆ LV2_ATOM_URI

#define LV2_ATOM_URI "http://lv2plug.in/ns/ext/atom"

http://lv2plug.in/ns/ext/atom

## ◆ LV2_ATOM_PREFIX

#define LV2_ATOM_PREFIX LV2_ATOM_URI "#"

http://lv2plug.in/ns/ext/atom#

## ◆ LV2_ATOM__Atom

#define LV2_ATOM__Atom LV2_ATOM_PREFIX "Atom"

http://lv2plug.in/ns/ext/atom#Atom

## ◆ LV2_ATOM__AtomPort

#define LV2_ATOM__AtomPort LV2_ATOM_PREFIX "AtomPort"

http://lv2plug.in/ns/ext/atom#AtomPort

## ◆ LV2_ATOM__Blank

#define LV2_ATOM__Blank LV2_ATOM_PREFIX "Blank"

http://lv2plug.in/ns/ext/atom#Blank

## ◆ LV2_ATOM__Bool

#define LV2_ATOM__Bool LV2_ATOM_PREFIX "Bool"

http://lv2plug.in/ns/ext/atom#Bool

## ◆ LV2_ATOM__Chunk

#define LV2_ATOM__Chunk LV2_ATOM_PREFIX "Chunk"

http://lv2plug.in/ns/ext/atom#Chunk

## ◆ LV2_ATOM__Double

#define LV2_ATOM__Double LV2_ATOM_PREFIX "Double"

http://lv2plug.in/ns/ext/atom#Double

## ◆ LV2_ATOM__Event

#define LV2_ATOM__Event LV2_ATOM_PREFIX "Event"

http://lv2plug.in/ns/ext/atom#Event

## ◆ LV2_ATOM__Float

#define LV2_ATOM__Float LV2_ATOM_PREFIX "Float"

http://lv2plug.in/ns/ext/atom#Float

## ◆ LV2_ATOM__Int

#define LV2_ATOM__Int LV2_ATOM_PREFIX "Int"

http://lv2plug.in/ns/ext/atom#Int

## ◆ LV2_ATOM__Literal

#define LV2_ATOM__Literal LV2_ATOM_PREFIX "Literal"

http://lv2plug.in/ns/ext/atom#Literal

## ◆ LV2_ATOM__Long

#define LV2_ATOM__Long LV2_ATOM_PREFIX "Long"

http://lv2plug.in/ns/ext/atom#Long

## ◆ LV2_ATOM__Number

#define LV2_ATOM__Number LV2_ATOM_PREFIX "Number"

http://lv2plug.in/ns/ext/atom#Number

## ◆ LV2_ATOM__Object

#define LV2_ATOM__Object LV2_ATOM_PREFIX "Object"

http://lv2plug.in/ns/ext/atom#Object

## ◆ LV2_ATOM__Path

#define LV2_ATOM__Path LV2_ATOM_PREFIX "Path"

http://lv2plug.in/ns/ext/atom#Path

## ◆ LV2_ATOM__Property

#define LV2_ATOM__Property LV2_ATOM_PREFIX "Property"

http://lv2plug.in/ns/ext/atom#Property

## ◆ LV2_ATOM__Resource

#define LV2_ATOM__Resource LV2_ATOM_PREFIX "Resource"

http://lv2plug.in/ns/ext/atom#Resource

## ◆ LV2_ATOM__Sequence

#define LV2_ATOM__Sequence LV2_ATOM_PREFIX "Sequence"

http://lv2plug.in/ns/ext/atom#Sequence

## ◆ LV2_ATOM__Sound

#define LV2_ATOM__Sound LV2_ATOM_PREFIX "Sound"

http://lv2plug.in/ns/ext/atom#Sound

## ◆ LV2_ATOM__String

#define LV2_ATOM__String LV2_ATOM_PREFIX "String"

http://lv2plug.in/ns/ext/atom#String

## ◆ LV2_ATOM__Tuple

#define LV2_ATOM__Tuple LV2_ATOM_PREFIX "Tuple"

http://lv2plug.in/ns/ext/atom#Tuple

## ◆ LV2_ATOM__URI

#define LV2_ATOM__URI LV2_ATOM_PREFIX "URI"

http://lv2plug.in/ns/ext/atom#URI

## ◆ LV2_ATOM__URID

#define LV2_ATOM__URID LV2_ATOM_PREFIX "URID"

http://lv2plug.in/ns/ext/atom#URID

## ◆ LV2_ATOM__Vector

#define LV2_ATOM__Vector LV2_ATOM_PREFIX "Vector"

http://lv2plug.in/ns/ext/atom#Vector

## ◆ LV2_ATOM__atomTransfer

#define LV2_ATOM__atomTransfer LV2_ATOM_PREFIX "atomTransfer"

http://lv2plug.in/ns/ext/atom#atomTransfer

## ◆ LV2_ATOM__beatTime

#define LV2_ATOM__beatTime LV2_ATOM_PREFIX "beatTime"

http://lv2plug.in/ns/ext/atom#beatTime

## ◆ LV2_ATOM__bufferType

#define LV2_ATOM__bufferType LV2_ATOM_PREFIX "bufferType"

http://lv2plug.in/ns/ext/atom#bufferType

## ◆ LV2_ATOM__childType

#define LV2_ATOM__childType LV2_ATOM_PREFIX "childType"

http://lv2plug.in/ns/ext/atom#childType

## ◆ LV2_ATOM__eventTransfer

#define LV2_ATOM__eventTransfer LV2_ATOM_PREFIX "eventTransfer"

http://lv2plug.in/ns/ext/atom#eventTransfer

## ◆ LV2_ATOM__frameTime

#define LV2_ATOM__frameTime LV2_ATOM_PREFIX "frameTime"

http://lv2plug.in/ns/ext/atom#frameTime

## ◆ LV2_ATOM__supports

#define LV2_ATOM__supports LV2_ATOM_PREFIX "supports"

http://lv2plug.in/ns/ext/atom#supports

## ◆ LV2_ATOM__timeUnit

#define LV2_ATOM__timeUnit LV2_ATOM_PREFIX "timeUnit"

http://lv2plug.in/ns/ext/atom#timeUnit

## ◆ LV2_ATOM_REFERENCE_TYPE

#define LV2_ATOM_REFERENCE_TYPE 0

The special type for a reference atom.

## ◆ LV2_ATOM_CONTENTS

#define LV2_ATOM_CONTENTS | ( |  | type,
|  |  | atom )

Value:
((void*)((uint8_t*)(atom) + sizeof(type)))

Return a pointer to the contents of an Atom.

The "contents" of an atom is the data past the complete type-specific header.

Parameters

  type | The type of the atom, for example LV2_Atom_String.
  atom | A variable-sized atom.

## ◆ LV2_ATOM_CONTENTS_CONST

#define LV2_ATOM_CONTENTS_CONST | ( |  | type,
|  |  | atom )

Value:
((const void*)((const uint8_t*)(atom) + sizeof(type)))

Const version of LV2_ATOM_CONTENTS.

## ◆ LV2_ATOM_BODY

#define LV2_ATOM_BODY | ( |  | atom | ) |

Value:
LV2_ATOM_CONTENTS(LV2_Atom, atom)
LV2_ATOM_CONTENTS
#define LV2_ATOM_CONTENTS(type, atom)
Return a pointer to the contents of an Atom.
Definition atom.h:77
LV2_Atom
The header of an atom:Atom.
Definition atom.h:97

Return a pointer to the body of an Atom.

The "body" of an atom is the data just past the LV2_Atom head (i.e. the same offset for all types).

## ◆ LV2_ATOM_BODY_CONST

#define LV2_ATOM_BODY_CONST | ( |  | atom | ) |

Value:
LV2_ATOM_CONTENTS_CONST(LV2_Atom, atom)
LV2_ATOM_CONTENTS_CONST
#define LV2_ATOM_CONTENTS_CONST(type, atom)
Const version of LV2_ATOM_CONTENTS.
Definition atom.h:82

Const version of LV2_ATOM_BODY.

## Typedef Documentation

## ◆ LV2_Atom_Bool

typedef LV2_Atom_Int LV2_Atom_Bool

An atom:Bool.

May be cast to LV2_Atom.