Components

Classes
struct	MMAL_COMPONENT_T

Typedefs
typedef struct MMAL_COMPONENT_PRIVATE_T	MMAL_COMPONENT_PRIVATE_T
typedef struct MMAL_COMPONENT_T	MMAL_COMPONENT_T

Functions
MMAL_STATUS_T	mmal_component_create (const char *name, MMAL_COMPONENT_T **component)
void	mmal_component_acquire (MMAL_COMPONENT_T *component)
MMAL_STATUS_T	mmal_component_release (MMAL_COMPONENT_T *component)
MMAL_STATUS_T	mmal_component_destroy (MMAL_COMPONENT_T *component)
MMAL_STATUS_T	mmal_component_enable (MMAL_COMPONENT_T *component)
MMAL_STATUS_T	mmal_component_disable (MMAL_COMPONENT_T *component)

Detailed Description

Definition of a MMAL component and its associated API. A component will always expose ports which it uses to send and receive data in the form of buffer headers (MMAL_BUFFER_HEADER_T)

Typedef Documentation

MMAL_COMPONENT_PRIVATE_T

typedef struct MMAL_COMPONENT_PRIVATE_T MMAL_COMPONENT_PRIVATE_T

Definition at line 45 of file mmal_component.h.

MMAL_COMPONENT_T

typedef struct MMAL_COMPONENT_T MMAL_COMPONENT_T

Definition of a component.

Function Documentation

mmal_component_acquire()

void mmal_component_acquire

(

MMAL_COMPONENT_T *

component

)

Acquire a reference on a component. Acquiring a reference on a component will prevent a component from being destroyed until the acquired reference is released (by a call to mmal_component_destroy). References are internally counted so all acquired references need a matching call to release them.

Parameters

component

component to acquire

mmal_component_create()

MMAL_STATUS_T mmal_component_create	(	const char *	name,
		MMAL_COMPONENT_T **	component
	)

Create an instance of a component. The newly created component will expose ports to the client. All the exposed ports are disabled by default. Note that components are reference counted and creating a component automatically acquires a reference to it (released when mmal_component_destroy is called).

Parameters

name	name of the component to create, e.g. "video_decode"
component	returned component

Returns

MMAL_SUCCESS on success

mmal_component_destroy()

MMAL_STATUS_T mmal_component_destroy

(

MMAL_COMPONENT_T *

component

)

Destroy a previously created component Release an acquired reference on a component. Only actually destroys the component when the last reference is being released.

Parameters

component

component to destroy

Returns

MMAL_SUCCESS on success

mmal_component_disable()

MMAL_STATUS_T mmal_component_disable

(

MMAL_COMPONENT_T *

component

)

Disable processing on a component

Parameters

component

component to disable

Returns

MMAL_SUCCESS on success

mmal_component_enable()

MMAL_STATUS_T mmal_component_enable

(

MMAL_COMPONENT_T *

component

)

Enable processing on a component

Parameters

component

component to enable

Returns

MMAL_SUCCESS on success

mmal_component_release()

MMAL_STATUS_T mmal_component_release

(

MMAL_COMPONENT_T *

component

)

Release a reference on a component Release an acquired reference on a component. Triggers the destruction of the component when the last reference is being released.

Note

This is in fact an alias of mmal_component_destroy which is added to make client code clearer.

Parameters

component

component to release

Returns

MMAL_SUCCESS on success