LibVLC Memory Management - Revision history

DoesItReallyMatter: +{{Lowercase}}, syntaxhighlight

2019-03-04T08:15:37Z

+{{Lowercase}}, syntaxhighlight

← Older revision		Revision as of 08:15, 4 March 2019
Line 1:		Line 1:
			{{Lowercase}}
	== Reference Counting ==		== Reference Counting ==

	[[~~LibVLC\|LibVLC~~]] uses a certain number of objects. Each one maintains a references count, which is used to know when the object must be released. The three related functions are:		[[libVLC]] uses a certain number of objects. Each one maintains a references count, which is used to know when the object must be released. The three related functions are:

	* libvlc_object_name_'''new'''() ''Create an object with a refcount equal to 1.''		* libvlc_object_name_'''new'''() ''Create an object with a refcount equal to 1.''

	* libvlc_object_name_'''retain'''() ''Increment the object refcount by 1.''		* libvlc_object_name_'''retain'''() ''Increment the object refcount by 1.''

	* libvlc_object_name_'''release'''() ''Decrement the refcount by 1, and release the object if the new refcount is less than zero.''		* libvlc_object_name_'''release'''() ''Decrement the refcount by 1, and release the object if the new refcount is less than zero.''

	=== Example ===		=== Example ===
			<syntaxhighlight lang="c">
	libvlc_media_list_t *p_ml = libvlc_media_list_new(libvlc_inst)		libvlc_media_list_t *p_ml = libvlc_media_list_new(libvlc_inst)

	/* Free the memory used by media_list release */		/* Free the memory used by media_list release */
	libvlc_media_list_release(p_ml);		libvlc_media_list_release(p_ml);
			</syntaxhighlight>

	=== Objects that don't follow this rule ===		=== Objects that don't follow this rule ===
Line 42:		Line 42:
	* libvlc_''object_name''_'''event_manager''': This getter never retains the object prior returning it. That means you '''mustn't release''' it.		* libvlc_''object_name''_'''event_manager''': This getter never retains the object prior returning it. That means you '''mustn't release''' it.

	[[Category:~~LibVLC~~]]		[[Category:libVLC]]

Funman: /* Objects that don't follow this rule */

2013-11-18T17:01:07Z

Objects that don't follow this rule

← Older revision		Revision as of 17:01, 18 November 2013
Line 18:		Line 18:
	=== Objects that don't follow this rule ===		=== Objects that don't follow this rule ===

	* libvlc_exception_t: Those are not pointers
	* libvlc_event_manager_t: Those are supposed to be accessed only during the life of their parent libvlc_* object.		* libvlc_event_manager_t: Those are supposed to be accessed only during the life of their parent libvlc_* object.

Funman: /* Example */

2013-11-18T17:00:40Z

Example

← Older revision		Revision as of 17:00, 18 November 2013
Line 11:		Line 11:
	=== Example ===		=== Example ===

	~~libvlc_exception_t e;~~		libvlc_media_list_t *p_ml = libvlc_media_list_new(libvlc_inst)
	~~libvlc_exception_init( &e );~~

	libvlc_media_list_t * p_ml = libvlc_media_list_new( libvlc_inst~~, &e~~)

	/* Free the memory used by media_list release */		/* Free the memory used by media_list release */
	libvlc_media_list_release( p_ml );		libvlc_media_list_release(p_ml);

	=== Objects that don't follow this rule ===		=== Objects that don't follow this rule ===

Edwardw: +category

2012-02-03T01:36:15Z

+category

← Older revision		Revision as of 01:36, 3 February 2012
Line 45:		Line 45:
	Notable exceptions to those rules are:		Notable exceptions to those rules are:
	* libvlc_''object_name''_'''event_manager''': This getter never retains the object prior returning it. That means you '''mustn't release''' it.		* libvlc_''object_name''_'''event_manager''': This getter never retains the object prior returning it. That means you '''mustn't release''' it.

			[[Category:LibVLC]]

Chrisberov: /* Reference Counting */

2011-11-28T12:38:07Z

Reference Counting

← Older revision		Revision as of 12:38, 28 November 2011
Line 1:		Line 1:
	== Reference Counting ==		== Reference Counting ==

	LibVLC uses a certain number of objects. Each one maintains a references count, which is used to know when the object must be released. The three related functions are:		[[LibVLC\|LibVLC]] uses a certain number of objects. Each one maintains a references count, which is used to know when the object must be released. The three related functions are:

	* libvlc_object_name_'''new'''() ''Create an object with a refcount equal to 1.''		* libvlc_object_name_'''new'''() ''Create an object with a refcount equal to 1.''

Pdherbemont at 00:09, 7 April 2008

2008-04-07T00:09:13Z

← Older revision		Revision as of 00:09, 7 April 2008
Line 8:		Line 8:

	* libvlc_object_name_'''release'''() ''Decrement the refcount by 1, and release the object if the new refcount is less than zero.''		* libvlc_object_name_'''release'''() ''Decrement the refcount by 1, and release the object if the new refcount is less than zero.''

	~~=== Objects that don't follow this rule ===~~

	* libvlc_exception_t: Those are not pointers
	* libvlc_event_manager_t: Those are supposed to be accessed only during the life of their parent libvlc_* object.

	=== Example ===		=== Example ===
Line 23:		Line 18:
	/* Free the memory used by media_list release */		/* Free the memory used by media_list release */
	libvlc_media_list_release( p_ml );		libvlc_media_list_release( p_ml );

			=== Objects that don't follow this rule ===

			* libvlc_exception_t: Those are not pointers
			* libvlc_event_manager_t: Those are supposed to be accessed only during the life of their parent libvlc_* object.

	== Getters and Setters ==		== Getters and Setters ==

Pdherbemont at 00:08, 7 April 2008

2008-04-07T00:08:17Z

← Older revision		Revision as of 00:08, 7 April 2008
Line 11:		Line 11:
	=== Objects that don't follow this rule ===		=== Objects that don't follow this rule ===

	~~???~~		* libvlc_exception_t: Those are not pointers
			* libvlc_event_manager_t: Those are supposed to be accessed only during the life of their parent libvlc_* object.

	=== Example ===		=== Example ===

Micha137: Editing

2008-01-13T16:20:10Z

Editing

← Older revision		Revision as of 16:20, 13 January 2008
Line 1:		Line 1:
	~~Todo: Improve readability.~~		== Reference Counting ==

	~~== Reference Counting ==~~		LibVLC uses a certain number of objects. Each one maintains a references count, which is used to know when the object must be released. The three related functions are:
	LibVLC uses a certain number of objects. Each one maintains a references count, which is used to know when the object must be released. The three related functions are:

	* libvlc_object_name_'''new'''() ''Create an object with a refcount ~~equals~~ to 1''		* libvlc_object_name_'''new'''() ''Create an object with a refcount equal to 1.''

	* libvlc_object_name_'''retain'''() ''Increment the object refcount by 1.''		* libvlc_object_name_'''retain'''() ''Increment the object refcount by 1.''
Line 10:		Line 9:
	* libvlc_object_name_'''release'''() ''Decrement the refcount by 1, and release the object if the new refcount is less than zero.''		* libvlc_object_name_'''release'''() ''Decrement the refcount by 1, and release the object if the new refcount is less than zero.''

	~~Object~~ that don't follow this rule:		=== Objects that don't follow this rule ===

			???

			=== Example ===

	~~=== Examples ===~~
	libvlc_exception_t e;		libvlc_exception_t e;
	libvlc_exception_init( &e );		libvlc_exception_init( &e );
Line 20:		Line 22:
	/* Free the memory used by media_list release */		/* Free the memory used by media_list release */
	libvlc_media_list_release( p_ml );		libvlc_media_list_release( p_ml );


	== Getters and Setters ==		== Getters and Setters ==
	Usually object ~~Property~~ are set through getters and setters.
			Usually object properties are set through getters and setters.

	* Usually getters are in the form:		* Usually getters are in the form:
Line 32:		Line 34:

	* Variations:		* Variations:

	** Setter: libvlc_media_list_add_media_descriptor		** Setter: libvlc_media_list_add_media_descriptor

	** Getter: libvlc_media_list_item_at_index		** Getter: libvlc_media_list_item_at_index

	For setters and getters the memory management rules are:		For setters and getters the memory management rules are:
	* Getters internally '''retain''' the object before returning it, so is means you must '''release''' the object after ~~uses~~.		* Getters internally '''retain''' the object before returning it, so is means you must '''release''' the object after use.
	* Setters internally '''retain''' the object, so basically you never need to keep the object around.		* Setters internally '''retain''' the object, so basically you never need to keep the object around.
	(This also applies to strings where retain is strdup and release is free)		(This also applies to strings where retain is '''strdup''' and release is '''free''')

	Notable exceptions to those rules are:		Notable exceptions to those rules are:
	* libvlc_''object_name''_'''event_manager''': This getter never ~~retain~~ the object prior returning it. That means you '''mustn't release''' it.		* libvlc_''object_name''_'''event_manager''': This getter never retains the object prior returning it. That means you '''mustn't release''' it.

Pdherbemont: Initial Creation.

2007-08-23T13:45:38Z

Initial Creation.

New page

Todo: Improve readability.

== Reference Counting ==
LibVLC uses a certain number of objects. Each one maintains a references count, which is used to know when the object must be released. The three related functions are:

* libvlc_object_name_'''new'''() ''Create an object with a refcount equals to 1''

* libvlc_object_name_'''retain'''() ''Increment the object refcount by 1.''

* libvlc_object_name_'''release'''() ''Decrement the refcount by 1, and release the object if the new refcount is less than zero.''

Object that don't follow this rule:

=== Examples ===
libvlc_exception_t e;
libvlc_exception_init( &e );

libvlc_media_list_t * p_ml = libvlc_media_list_new( libvlc_inst, &e)

/* Free the memory used by media_list release */
libvlc_media_list_release( p_ml );

== Getters and Setters ==
Usually object Property are set through getters and setters.

* Usually getters are in the form:
libvlc_''object_name''_''object''

* Setters are:
libvlc_''object_name''_''set_object''

* Variations:

** Setter: libvlc_media_list_add_media_descriptor

** Getter: libvlc_media_list_item_at_index

For setters and getters the memory management rules are:
* Getters internally '''retain''' the object before returning it, so is means you must '''release''' the object after uses.
* Setters internally '''retain''' the object, so basically you never need to keep the object around.
(This also applies to strings where retain is strdup and release is free)

Notable exceptions to those rules are:
* libvlc_''object_name''_'''event_manager''': This getter never retain the object prior returning it. That means you '''mustn't release''' it.