xref: /haiku/docs/user/book.dox (revision f122405db872d2a0e65bdb33305b9d1080016627)
10524a6a8Smahlzeit/*!
26ac7032dSJohn Scipione	\mainpage Welcome to the Haiku Book
36ac7032dSJohn Scipione
46ac7032dSJohn Scipione	Below you will find documentation on the Application Programming
56ac7032dSJohn Scipione	Interface (API) of the Haiku operating system. This API describes
66ac7032dSJohn Scipione	the internals of the operating system allowing developers to write
76ac7032dSJohn Scipione	native C++ applications and device drivers. See the
81de2d728SAugustin Cavalier	<a href="https://api.haiku-os.org">online version</a> for the most
96ac7032dSJohn Scipione	updated version of this document. If you would like to help contribute
104d556706SAugustin Cavalier	contact the <a href="https://www.freelists.org/list/haiku-doc">documentation
116ac7032dSJohn Scipione	mailing list</a>. For guidelines on how to help document the API see
126ac7032dSJohn Scipione	the \link apidoc Documenting the API\endlink page. A list of
136ac7032dSJohn Scipione	contributors can be found \ref credits page. Documenting the API is
146ac7032dSJohn Scipione	an ongoing process so contributions are greatly appreciated.
156ac7032dSJohn Scipione
166ac7032dSJohn Scipione	The Haiku API is based on the BeOS R5 API but changes and additions have
176ac7032dSJohn Scipione	been included where appropriate. Important compatibility differences are
186ac7032dSJohn Scipione	detailed on the \ref compatibility page. New classes and methods
196ac7032dSJohn Scipione	and incompatible API changes to the BeOS R5 API are noted in the
206ac7032dSJohn Scipione	appropriate sections.
216ac7032dSJohn Scipione
226ac7032dSJohn Scipione	A complete reference to the BeOS R5 API is available on the web in
231de2d728SAugustin Cavalier	<a href="https://haiku-os.org/legacy-docs/bebook/">The Be Book</a>.
246ac7032dSJohn Scipione	The Be Book is used with permission from
254d556706SAugustin Cavalier	<a href="https://www.access-company.com/">Access Co.</a>, the current
266ac7032dSJohn Scipione	owners of Be's intellectual property.
270524a6a8Smahlzeit
281e994bc7SJohn Scipione	\section book_kits Kits and Servers
290524a6a8Smahlzeit
306ac7032dSJohn Scipione	The API is split into several kits and servers each detailing a different
316ac7032dSJohn Scipione	aspect of the operating system.
326ac7032dSJohn Scipione		- The \ref app is the starting point for developing applications
336ac7032dSJohn Scipione			and includes classes for messaging and for interacting with
346ac7032dSJohn Scipione			the rest of the system.
358786818cSJohn Scipione		- The \ref game provides classes for producing game sounds and
368786818cSJohn Scipione			working with full screen apps.
376ac7032dSJohn Scipione		- The \ref interface is used to create responsive and attractive
386ac7032dSJohn Scipione			graphical user interfaces building on the messaging facilities
396ac7032dSJohn Scipione			provided by the Application Kit.
40*f122405dSAdrien Destugues			- A \link interface_intro general introduction \endlink to the
41*f122405dSAdrien Destugues				Interface Kit.
426ac7032dSJohn Scipione			- The \link layout_intro Layout API \endlink is a new addition
436ac7032dSJohn Scipione				to the Interface Kit in Haiku which provides resources to
446ac7032dSJohn Scipione				layout your application flexibly and easily.
456ac7032dSJohn Scipione		- The \ref locale includes classes to localize your application to
466ac7032dSJohn Scipione			different languages, timezones, number formatting conventions and
476ac7032dSJohn Scipione			much more.
4895c9effdSAugustin Cavalier		- The \ref mail includes classes to work with e-mail files, folders,
4995c9effdSAugustin Cavalier			protocols, and filters, as part of Haiku's unique mail handling system.
506ac7032dSJohn Scipione		- The \ref media provides a unified and consistent interface for media
516ac7032dSJohn Scipione			streams and applications to intercommunicate.
526ac7032dSJohn Scipione		- The \ref midi2 describes an interface to generating, processing,
536ac7032dSJohn Scipione			and playing music in MIDI format. For reference documentation on the
546ac7032dSJohn Scipione			\ref midi1 is also included.
554cf62172SAdrien Destugues		- The \ref network handles everything network related, from interface
564cf62172SAdrien Destugues			IP address settings to HTTP connections.
576ac7032dSJohn Scipione		- The \ref storage is a collection of classes that deal with storing and
586ac7032dSJohn Scipione			retrieving information from disk.
596ac7032dSJohn Scipione		- The \ref support contains support classes to use in your application
606ac7032dSJohn Scipione			including resources for thread safety, IO, and serialization.
613528f5bbSJohn Scipione		- The \ref translation provides a framework for converting data streams
623528f5bbSJohn Scipione			between media formats.
6389e18a51SNiels Sascha Reedijk
641e994bc7SJohn Scipione	\section book_special_topics Special Topics
656ac7032dSJohn Scipione
66b966e837SAdrien Destugues	- \ref libroot
676ac7032dSJohn Scipione	- \ref drivers
684466b89cSJohn Scipione	- \ref keyboard
69f943fa46SAndrew Lindesay	- \ref json
70094b8dcfSNiels Sascha Reedijk	- \ref netservices
71d419ca3bSNiels Sascha Reedijk*/
72d419ca3bSNiels Sascha Reedijk
739889ca4aSNiels Sascha Reedijk///// Define main kits /////
7489e18a51SNiels Sascha Reedijk
75d419ca3bSNiels Sascha Reedijk/*!
76bef614efSNiels Sascha Reedijk	\defgroup app Application Kit
776ac7032dSJohn Scipione	\brief The Application Kit is the starting point for writing native Haiku
786ac7032dSJohn Scipione		GUI applications.
796ac7032dSJohn Scipione
806ac7032dSJohn Scipione	The application kit is exactly what its name suggests &mdash; it is the
816ac7032dSJohn Scipione	basis of Haiku applications. You should first read through this document
826ac7032dSJohn Scipione	and the references here before moving on to the other parts of the API.
836ac7032dSJohn Scipione
846ac7032dSJohn Scipione	The Application Kit classes can be divided into two groups: the messaging
856ac7032dSJohn Scipione	classes and the system interaction classes. The larger of the two groups is
866ac7032dSJohn Scipione	the messaging classes. Since the Haiku API relies on pervasive
876ac7032dSJohn Scipione	multithreading messaging is an essential topic for any application. Have a
886ac7032dSJohn Scipione	look at the \link app_messaging Introduction to Messaging \endlink for more
896ac7032dSJohn Scipione	information.
906ac7032dSJohn Scipione
916ac7032dSJohn Scipione	The following messaging classes which allow you to easily and securely
926ac7032dSJohn Scipione	communicate between threads.
936ac7032dSJohn Scipione		- BHandler
946ac7032dSJohn Scipione		- BInvoker
956ac7032dSJohn Scipione		- BLooper
966ac7032dSJohn Scipione		- BMessage
976ac7032dSJohn Scipione		- BMessageFilter
986ac7032dSJohn Scipione		- BMessageQueue
996ac7032dSJohn Scipione		- BMessageRunner
1006ac7032dSJohn Scipione		- BMessenger
1016ac7032dSJohn Scipione
1026ac7032dSJohn Scipione	The second group is the system interaction classes. These classes
1036ac7032dSJohn Scipione	provide hooks for your application to interact with the rest of the system.
1046ac7032dSJohn Scipione	The most important class in this group is BApplication. Below is a list of
1056ac7032dSJohn Scipione	all system interaction classes:
1066ac7032dSJohn Scipione		- BApplication
1076ac7032dSJohn Scipione		- BClipboard
1086ac7032dSJohn Scipione		- BCursor
1090e6f9572SNiels Sascha Reedijk		- BLaunchRoster
1100e6f9572SNiels Sascha Reedijk		- BNotification
1116ac7032dSJohn Scipione		- BPropertyInfo
1126ac7032dSJohn Scipione		- BRoster
1136ac7032dSJohn Scipione
1140e6f9572SNiels Sascha Reedijk	A third special category is the \link app_keystore Password and Key storage
1150e6f9572SNiels Sascha Reedijk	API:\endlink
1160e6f9572SNiels Sascha Reedijk		- BKey
1170e6f9572SNiels Sascha Reedijk		- BKeyStore
1180e6f9572SNiels Sascha Reedijk
1196ac7032dSJohn Scipione
1208786818cSJohn Scipione	\defgroup game Game Kit
1218786818cSJohn Scipione	\brief The Game Kit provides classes for producing game sounds and
1228786818cSJohn Scipione		working with full screen apps.
1238786818cSJohn Scipione
1248786818cSJohn Scipione
125cc19e7c0SAlex Wilson	\defgroup interface Interface Kit
126cc19e7c0SAlex Wilson	\brief API for displaying a graphical user interface.
1276ac7032dSJohn Scipione
1286ac7032dSJohn Scipione	The Interface Kit holds all the classes you'll need to develop a GUI.
1296ac7032dSJohn Scipione	Building on the messaging facilities provided by the Application Kit,
1306ac7032dSJohn Scipione	the Interface Kit can be used to create a responsive and attractive
1316ac7032dSJohn Scipione	graphical user interface.
1326ac7032dSJohn Scipione
1336ac7032dSJohn Scipione 	The most important class in the Interface Kit is the BView class, which
1346ac7032dSJohn Scipione	handles drawing and user interaction. Pointer and keyboard events are
1356ac7032dSJohn Scipione	processed in this class.
1366ac7032dSJohn Scipione
1376ac7032dSJohn Scipione	Another important class is the BWindow class, which holds BViews and makes
1386ac7032dSJohn Scipione	them visible to the user. The BWindow class also handles BView focusing
1396ac7032dSJohn Scipione	and BMessage dispatching, among other things.
1406ac7032dSJohn Scipione
1416ac7032dSJohn Scipione	A new addition Haiku has added over the BeOS API is the Layout API, which
1426ac7032dSJohn Scipione	is based around the BLayoutItem and BLayout classes. These classes will
1436ac7032dSJohn Scipione	take care of making sure all your GUI widgets end up where you want them,
1446ac7032dSJohn Scipione	with enough space to be useful. You can start learning the Layout API
1456ac7032dSJohn Scipione	by reading the \link layout_intro introduction \endlink.
1466ac7032dSJohn Scipione
1476ac7032dSJohn Scipione
1480a4e27c5SAdrien Destugues	\defgroup locale Locale Kit
149c6247544SAdrien Destugues	\brief Collection of classes for localizing applications.
1506ac7032dSJohn Scipione
15195c9effdSAugustin Cavalier	\defgroup mail Mail Kit
15295c9effdSAugustin Cavalier	\brief API for working with e-mail messages and protocols.
15395c9effdSAugustin Cavalier
1546ac7032dSJohn Scipione	\defgroup media Media Kit
1556ac7032dSJohn Scipione	\brief Collection of classes that deal with audio and video.
1566ac7032dSJohn Scipione
1576ac7032dSJohn Scipione	\defgroup midi1 The old MIDI Kit (libmidi.so)
1586ac7032dSJohn Scipione	\brief The old MIDI kit.
1596ac7032dSJohn Scipione
1606ac7032dSJohn Scipione
1616ac7032dSJohn Scipione	\defgroup midi2 MIDI 2 Kit
1626ac7032dSJohn Scipione	\brief The Midi Kit is the API that implements support for generating,
1636ac7032dSJohn Scipione		processing, and playing music in MIDI format.
1646ac7032dSJohn Scipione
1654d556706SAugustin Cavalier	<A HREF="https://www.midi.org/">MIDI</A>, which  stands for 'Musical
1666ac7032dSJohn Scipione	Instrument Digital Interface', is a well-established  standard for
1676ac7032dSJohn Scipione	representing and communicating musical data. This document serves as
1686ac7032dSJohn Scipione	an overview. If you would like to see all the components, please look
1696ac7032dSJohn Scipione	at \link midi2 the list with classes \endlink.
1706ac7032dSJohn Scipione
1711e994bc7SJohn Scipione	\section book_midi2twokits A Tale of Two MIDI Kits
1726ac7032dSJohn Scipione
1736ac7032dSJohn Scipione	BeOS comes with two different, but compatible Midi Kits. This
1746ac7032dSJohn Scipione	documentation focuses on the "new" Midi Kit, or midi2 as we like to
1756ac7032dSJohn Scipione	call it, that was  introduced with BeOS R5. The old kit, which we'll
1766ac7032dSJohn Scipione	refer to as midi1, is more complete than the new kit, but less powerful.
1776ac7032dSJohn Scipione
1786ac7032dSJohn Scipione	Both kits let you create so-called MIDI endpoints, but the endpoints
1796ac7032dSJohn Scipione	from midi1 cannot be shared between different applications. The midi2
1806ac7032dSJohn Scipione	kit solves that  problem, but unlike midi1 it does not include a General
1816ac7032dSJohn Scipione	MIDI softsynth, nor does it have a facility for reading and playing
1826ac7032dSJohn Scipione	Standard MIDI Files. Don't worry: both kits are compatible and you can
1836ac7032dSJohn Scipione	mix-and-match them in your applications.
1846ac7032dSJohn Scipione
1856ac7032dSJohn Scipione	The main differences between the two kits:
1866ac7032dSJohn Scipione		- Instead of one BMidi object that both produces and consumes events,
1876ac7032dSJohn Scipione			we have BMidiProducer and BMidiConsumer.
1886ac7032dSJohn Scipione		- Applications are capable of sharing MIDI producers and consumers
1896ac7032dSJohn Scipione			with other applications via the centralized Midi Roster.
1906ac7032dSJohn Scipione		- Physical MIDI ports are now sharable without apps "stealing" events
1916ac7032dSJohn Scipione			from each other.
1926ac7032dSJohn Scipione		- Applications can now send/receive raw MIDI byte streams (useful if
1936ac7032dSJohn Scipione			an application has its own MIDI parser/engine).
1946ac7032dSJohn Scipione		- Channels are numbered 0&ndash;15, not 1&ndash;16
1956ac7032dSJohn Scipione		- Timing is now specified in microseconds rather than milliseconds.
1966ac7032dSJohn Scipione
1971e994bc7SJohn Scipione	\section book_midi2concepts Midi Kit Concepts
1986ac7032dSJohn Scipione
1996ac7032dSJohn Scipione	A brief overview of the elements that comprise the Midi Kit:
2006ac7032dSJohn Scipione		- \b Endpoints. This is what the Midi Kit is all about: sending MIDI
2016ac7032dSJohn Scipione			messages between endpoints. An endpoint is like a MIDI In or MIDI
2026ac7032dSJohn Scipione			Out socket on your equipment; it either receives information or it
2036ac7032dSJohn Scipione			sends information. Endpoints that send MIDI events are called
2046ac7032dSJohn Scipione			\b producers; the endpoints that receive those events are called
2056ac7032dSJohn Scipione			\b consumers. An endpoint that is created by your own application
2066ac7032dSJohn Scipione			is called \b local; endpoints from other applications are
2076ac7032dSJohn Scipione			\b remote. You can access remote endpoints using \b proxies.
2086ac7032dSJohn Scipione		- \b Filters. A filter is an object that has a consumer and a producer
2096ac7032dSJohn Scipione			endpoint. It reads incoming events from its consumer, performs some
2106ac7032dSJohn Scipione			operation, and tells its producer to send out the results. In its
2116ac7032dSJohn Scipione			current form, the Midi  Kit doesn't provide any special facilities
2126ac7032dSJohn Scipione			for writing filters.
2136ac7032dSJohn Scipione		- \b Midi \b Roster. The roster is the list of all published producers
2146ac7032dSJohn Scipione			and consumers. By publishing an endpoint, you allow other
2156ac7032dSJohn Scipione			applications to talk to it. You are not required to publish your
2166ac7032dSJohn Scipione			endpoints, in which case only your own application can use them.
2176ac7032dSJohn Scipione		- \b Midi \b Server. The Midi Server does the behind-the-scenes work.
2186ac7032dSJohn Scipione			It manages the roster, it connects endpoints, it makes sure that
2196ac7032dSJohn Scipione			endpoints can communicate, and so on. The Midi Server is started
2206ac7032dSJohn Scipione			automatically when BeOS boots, and you never have to deal with it
2216ac7032dSJohn Scipione			directly. Just remember that it runs the show.
2226ac7032dSJohn Scipione		- \b libmidi. The BMidi* classes live inside two shared libraries:
2236ac7032dSJohn Scipione			libmidi.so and libmidi2.so. If you write an application that uses
2246ac7032dSJohn Scipione			old Midi Kit, you must link it to libmidi.so. Applications that use
2256ac7032dSJohn Scipione			the new Midi Kit must link to libmidi2.so. If you want to
2266ac7032dSJohn Scipione			mix-and-match both kits, you should also link to both libraries.
2276ac7032dSJohn Scipione
2286ac7032dSJohn Scipione	Here is a pretty picture:
2296ac7032dSJohn Scipione
2306ac7032dSJohn Scipione	\image html midi2concepts.png
2316ac7032dSJohn Scipione
2321e994bc7SJohn Scipione	\section book_midi2mediakit Midi Kit != Media Kit
2336ac7032dSJohn Scipione
2346ac7032dSJohn Scipione	Be chose not to integrate the Midi Kit into the Media Kit as another media
2356ac7032dSJohn Scipione	type, mainly because MIDI doesn't require any of the format negotiation that
2366ac7032dSJohn Scipione	other media types need. Although the two kits look similar -- both have a
2376ac7032dSJohn Scipione	"roster" for finding or registering "consumers" and "producers" -- there are
2386ac7032dSJohn Scipione	some very important differences.
2396ac7032dSJohn Scipione
2406ac7032dSJohn Scipione	The first and most important point to note is that BMidiConsumer and
2416ac7032dSJohn Scipione	BMidiProducer in the Midi Kit are \b NOT directly analogous to
2426ac7032dSJohn Scipione	BBufferConsumer and  BBufferProducer in the Media Kit! In the Media Kit,
2436ac7032dSJohn Scipione	consumers and producers are the data consuming and producing properties
2446ac7032dSJohn Scipione	of a media node. A filter in the Media Kit, therefore, inherits from both
2456ac7032dSJohn Scipione	BBufferConsumer and BBufferProducer, and implements their virtual member
2466ac7032dSJohn Scipione	functions to do its work.
2476ac7032dSJohn Scipione
2486ac7032dSJohn Scipione	In the Midi Kit, consumers and producers act as endpoints of MIDI data
2496ac7032dSJohn Scipione	connections, much as media_source and media_destination do in the Media Kit.
2506ac7032dSJohn Scipione	Thus, a MIDI filter does not derive from BMidiConsumer and BMidiProducer;
2516ac7032dSJohn Scipione	instead, it contains BMidiConsumer and BMidiProducer objects for each of its
2526ac7032dSJohn Scipione	distinct endpoints that connect to other MIDI objects. The Midi Kit does not
2536ac7032dSJohn Scipione	allow the use of multiple virtual inheritance, so you can't create an object
2546ac7032dSJohn Scipione	that's both a BMidiConsumer and a BMidiProducer.
2556ac7032dSJohn Scipione
2566ac7032dSJohn Scipione	This also contrasts with the old Midi Kit's conception of a BMidi object,
2576ac7032dSJohn Scipione	which stood for an object that both received and sent MIDI data. In the new
2586ac7032dSJohn Scipione	Midi Kit, the endpoints of MIDI connections are all that matters. What lies
2596ac7032dSJohn Scipione	between the endpoints, i.e. how a MIDI filter is actually structured, is
2606ac7032dSJohn Scipione	entirely at your discretion.
2616ac7032dSJohn Scipione
2626ac7032dSJohn Scipione	Also, rather than use token structs like media_node to make connections
2636ac7032dSJohn Scipione	via the MediaRoster, the new kit makes the connections directly via the
2646ac7032dSJohn Scipione	BMidiProducer object.
2656ac7032dSJohn Scipione
2661e994bc7SJohn Scipione	\section book_midi2remotelocal Remote vs. Local Objects
2676ac7032dSJohn Scipione
2686ac7032dSJohn Scipione	The Midi Kit makes a distinction between remote and local MIDI objects.
2696ac7032dSJohn Scipione	You can  only create local MIDI endpoints, which derive from either
2706ac7032dSJohn Scipione	BMidiLocalConsumer or BMidiLocalProducer. Remote endpoints are endpoints
2716ac7032dSJohn Scipione	that live in other applications, and you access them through BMidiRoster.
2726ac7032dSJohn Scipione
2736ac7032dSJohn Scipione	BMidiRoster only gives you access to BMidiEndpoints, BMidiConsumers, and
2746ac7032dSJohn Scipione	BMidiProducers. When you want to talk to remote MIDI objects, you do so
2756ac7032dSJohn Scipione	through the proxy objects that BMidiRoster provides. Unlike
2766ac7032dSJohn Scipione	BMidiLocalConsumer and BMidiLocalProducer, these classes do not provide a
2776ac7032dSJohn Scipione	lot of functions. That is intentional. In order to hide the details of
2786ac7032dSJohn Scipione	communication with MIDI endpoints in other applications, the Midi Kit must
2796ac7032dSJohn Scipione	hide the details of how a particular endpoint is implemented.
2806ac7032dSJohn Scipione
2816ac7032dSJohn Scipione	So what can you do with remote objects? Only what BMidiConsumer,
2826ac7032dSJohn Scipione	BMidiProducer, and BMidiEndpoint will let you do. You can connect
2836ac7032dSJohn Scipione	objects, get the properties of these objects -- and that's about it.
2846ac7032dSJohn Scipione
2851e994bc7SJohn Scipione	\section book_midi2lifespan Creating and Destroying Objects
2866ac7032dSJohn Scipione
2876ac7032dSJohn Scipione	The constructors and destructors of most midi2 classes are private,
2886ac7032dSJohn Scipione	which means that you cannot directly create them using the C++
2896ac7032dSJohn Scipione	<CODE>new</CODE> operator, on the  stack, or as globals. Nor can you
2906ac7032dSJohn Scipione	<CODE>delete</CODE> them. Instead, these objects are obtained through
2916ac7032dSJohn Scipione	BMidiRoster. The only two exceptions to this rule are BMidiLocalConsumer
2926ac7032dSJohn Scipione	and BMidiLocalProducer. These two objects may be directly created and
2936ac7032dSJohn Scipione	subclassed by developers.
2946ac7032dSJohn Scipione
2951e994bc7SJohn Scipione	\section book_midi2refcount Reference Counting
2966ac7032dSJohn Scipione
2976ac7032dSJohn Scipione	Each MIDI endpoint has a reference count associated with it, so that
2986ac7032dSJohn Scipione	the Midi Roster can do proper bookkeeping. When you construct a
2996ac7032dSJohn Scipione	BMidiLocalProducer or  BMidiLocalConsumer endpoint, it starts with a
3006ac7032dSJohn Scipione	reference count of 1. In addition, BMidiRoster increments the reference
3016ac7032dSJohn Scipione	count of any object it hands to you as a result of
3026ac7032dSJohn Scipione	\link BMidiRoster::NextEndpoint() NextEndpoint() \endlink or
3036ac7032dSJohn Scipione	\link BMidiRoster::FindEndpoint() FindEndpoint() \endlink.
3046ac7032dSJohn Scipione	Once the count hits  0, the endpoint will be deleted.
3056ac7032dSJohn Scipione
3066ac7032dSJohn Scipione	This means that, to delete an endpoint, you don't call the
3076ac7032dSJohn Scipione	<CODE>delete</CODE>  operator directly; instead, you call
3086ac7032dSJohn Scipione	\link BMidiEndpoint::Release() Release() \endlink.
3096ac7032dSJohn Scipione	To balance this call, there's also an
3106ac7032dSJohn Scipione	\link BMidiEndpoint::Acquire() Acquire() \endlink, in case you have two
3116ac7032dSJohn Scipione	disparate parts of your application working with the endpoint, and you
3126ac7032dSJohn Scipione	don't want to have to keep track of who needs to Release() the endpoint.
3136ac7032dSJohn Scipione
3146ac7032dSJohn Scipione	When you're done with any endpoint object, you must Release() it.
3156ac7032dSJohn Scipione	This is true  for both local and remote objects. Repeat after me:
3166ac7032dSJohn Scipione	Release() when you're done.
3176ac7032dSJohn Scipione
3181e994bc7SJohn Scipione	\section book_midi2events MIDI Events
3196ac7032dSJohn Scipione
3206ac7032dSJohn Scipione	To make some actual music, you need to
3216ac7032dSJohn Scipione	\link BMidiProducer::Connect() Connect() \endlink your consumers to
3226ac7032dSJohn Scipione	your producers. Then you tell the producer to "spray" MIDI events to all
3236ac7032dSJohn Scipione	the connected consumers. The consumers are notified of these incoming
3246ac7032dSJohn Scipione	events through a set of hook functions.
3256ac7032dSJohn Scipione
3266ac7032dSJohn Scipione	The Midi Kit already provides a set of commonly used spray functions,
3276ac7032dSJohn Scipione	such as  \link BMidiLocalProducer::SprayNoteOn() SprayNoteOn() \endlink,
3286ac7032dSJohn Scipione	\link BMidiLocalProducer::SprayControlChange() SprayControlChange()
3296ac7032dSJohn Scipione	\endlink, and so on. These correspond one-to-one with the message types
3306ac7032dSJohn Scipione	from the MIDI spec. You don't need to be a MIDI expert to use the kit, but
3316ac7032dSJohn Scipione	of course some knowledge of the protocol helps. If you are really hardcore,
3326ac7032dSJohn Scipione	you can also use the
3336ac7032dSJohn Scipione	\link BMidiLocalProducer::SprayData() SprayData() \endlink to send raw MIDI
3346ac7032dSJohn Scipione	events to the consumers.
3356ac7032dSJohn Scipione
3366ac7032dSJohn Scipione	At the consumer side, a dedicated thread invokes a hook function for every
3376ac7032dSJohn Scipione	incoming MIDI event. For every spray function, there is a corresponding hook
3386ac7032dSJohn Scipione	function, e.g. \link BMidiLocalConsumer::NoteOn() NoteOn() \endlink and
3396ac7032dSJohn Scipione	\link  BMidiLocalConsumer::ControlChange() ControlChange() \endlink.
3406ac7032dSJohn Scipione	The hardcore MIDI fanatics among you will be pleased to know that you can
3416ac7032dSJohn Scipione	also tap into the \link BMidiLocalConsumer::Data() Data() \endlink hook and
3426ac7032dSJohn Scipione	get your hands dirty with the raw MIDI data.
3436ac7032dSJohn Scipione
3441e994bc7SJohn Scipione	\section book_midi2time Time
3456ac7032dSJohn Scipione
3466ac7032dSJohn Scipione	The spray and hook functions accept a bigtime_t parameter named "time". This
3476ac7032dSJohn Scipione	indicates when the MIDI event should be performed. The time is given in
3486ac7032dSJohn Scipione	microseconds since the computer booted. To get the current tick measurement,
3496ac7032dSJohn Scipione	you call the system_time() function from the Kernel Kit.
3506ac7032dSJohn Scipione
3516ac7032dSJohn Scipione	If you override a hook function in one of your consumer objects, it should
3526ac7032dSJohn Scipione	look  at the time argument, wait until the designated time, and then perform
3536ac7032dSJohn Scipione	its action. The preferred method is to use the Kernel Kit's
3546ac7032dSJohn Scipione	<CODE>snooze_until()</CODE> function, which sends the consumer thread to
3556ac7032dSJohn Scipione	sleep  until the requested time has come. (Or, if the time has already
3566ac7032dSJohn Scipione	passed, returns immediately.)
3576ac7032dSJohn Scipione
3586ac7032dSJohn Scipione	Like this:
3596ac7032dSJohn Scipione
3606ac7032dSJohn Scipione	\code
3616ac7032dSJohn Scipionevoid MyConsumer::NoteOn(
3626ac7032dSJohn Scipione    uchar channel, uchar note, uchar velocity, bigtime_t time)
3636ac7032dSJohn Scipione{
3646ac7032dSJohn Scipione    snooze_until(time, B_SYSTEM_TIMEBASE);
3656ac7032dSJohn Scipione    ...do your thing...
3666ac7032dSJohn Scipione}
3676ac7032dSJohn Scipione	\endcode
3686ac7032dSJohn Scipione
3696ac7032dSJohn Scipione	If you want your producers to run in real time, i.e. they produce MIDI data
3706ac7032dSJohn Scipione	that needs to be performed immediately, you should pass time 0 to the spray
3716ac7032dSJohn Scipione	functions (which also happens to be the default value). Since time 0 has
3726ac7032dSJohn Scipione	already passed, <CODE>snooze_until()</CODE> returns immediately, and the
3736ac7032dSJohn Scipione	consumer will process the events as soon as they are received.
3746ac7032dSJohn Scipione
3756ac7032dSJohn Scipione	To schedule MIDI events for a performance time that lies somewhere in the
3766ac7032dSJohn Scipione	future, the producer must take into account the consumer's latency.
3776ac7032dSJohn Scipione	Producers  should attempt to get notes to the consumer by or before
3786ac7032dSJohn Scipione	<I>(scheduled_performance_time - latency)</I>. The time argument is still
3796ac7032dSJohn Scipione	the scheduled performance time, so if your consumer has latency, it should
3806ac7032dSJohn Scipione	snooze like this before it starts to perform the events:
3816ac7032dSJohn Scipione
3826ac7032dSJohn Scipione	\code
3836ac7032dSJohn Scipionesnooze_until(time - Latency(), B_SYSTEM_TIMEBASE);
3846ac7032dSJohn Scipione	\endcode
3856ac7032dSJohn Scipione
3866ac7032dSJohn Scipione	Note that a typical producer sends out its events as soon as it can;
3876ac7032dSJohn Scipione	unlike a consumer, it does not have to snooze.
3886ac7032dSJohn Scipione
3891e994bc7SJohn Scipione	\section book_midi2ports Other Timing Issues
3906ac7032dSJohn Scipione
3916ac7032dSJohn Scipione	Each consumer object uses a Kernel Kit port to receive MIDI events from
3926ac7032dSJohn Scipione	connected producers. The queue for this port is only 1 message deep.
3936ac7032dSJohn Scipione	This means that if the consumer thread is asleep in a
3946ac7032dSJohn Scipione	<CODE>snooze_until()</CODE>, it will not read its port. Consequently,
3956ac7032dSJohn Scipione	any producer that tries to write a new event to this port will block until
3966ac7032dSJohn Scipione	the consumer thread is ready to receive a new message. This is intentional,
3976ac7032dSJohn Scipione	because it prevents producers from generating and queueing up thousands of
3986ac7032dSJohn Scipione	events.
3996ac7032dSJohn Scipione
4006ac7032dSJohn Scipione	This mechanism, while simple, puts on the producer the responsibility
4016ac7032dSJohn Scipione	for sorting the events in time. Suppose your producer sends three Note
4026ac7032dSJohn Scipione	On events, the first on t + 0, the second on t + 4, and the third on t + 2.
4036ac7032dSJohn Scipione	This last event won't be received until after t + 4, so it will be two ticks
4046ac7032dSJohn Scipione	too late. If this sort of thing can happen with your producer, you should
4056ac7032dSJohn Scipione	somehow sort the events before you spray them. Of course, if you have two or
4066ac7032dSJohn Scipione	more producers connected to the same consumer, it is nearly impossible to
4076ac7032dSJohn Scipione	sort this all out (pardon the pun). So it is not wise to send the same kinds
4086ac7032dSJohn Scipione	of events from more than one producer to one consumer at the same time.
4096ac7032dSJohn Scipione
4106ac7032dSJohn Scipione	The article Introduction to MIDI, Part 2 in <A
4114d556706SAugustin Cavalier	HREF="https://open-beos.sourceforge.net/nsl.php?mode=display&id=36">OpenBeOS
4126ac7032dSJohn Scipione	Newsletter 36</A> describes this problem in more detail, and provides a
4136ac7032dSJohn Scipione	solution. Go read it now!
4146ac7032dSJohn Scipione
4151e994bc7SJohn Scipione	\section book_midi2filters Writing a Filter
4166ac7032dSJohn Scipione
4176ac7032dSJohn Scipione	A typical filter contains a consumer and a producer endpoint. It receives
4186ac7032dSJohn Scipione	events from the consumer, processes them, and sends them out again using the
4196ac7032dSJohn Scipione	producer. The consumer endpoint is a subclass of BMidiLocalConsumer, whereas
4206ac7032dSJohn Scipione	the producer is simply a BMidiLocalProducer, not a subclass. This is a
4216ac7032dSJohn Scipione	common  configuration, because consumers work by overriding the event hooks
4226ac7032dSJohn Scipione	to do work  when MIDI data arrives. Producers work by sending an event when
4236ac7032dSJohn Scipione	you call their  member functions. You should hardly ever need to derive from
4246ac7032dSJohn Scipione	BMidiLocalProducer (unless you need to know when the producer gets connected
4256ac7032dSJohn Scipione	or disconnected, perhaps), but you'll always have to override one or more of
4266ac7032dSJohn Scipione	BMidiLocalConsumer's member functions to do something useful with incoming
4276ac7032dSJohn Scipione	data.
4286ac7032dSJohn Scipione
4296ac7032dSJohn Scipione	Filters should ignore the time argument from the spray and hook functions,
4306ac7032dSJohn Scipione	and  simply pass it on unchanged. Objects that only filter data should
4316ac7032dSJohn Scipione	process the  event as quickly as possible and be done with it. Do not
4326ac7032dSJohn Scipione	<CODE>snooze_until()</CODE> in the consumer endpoint of a filter!
4336ac7032dSJohn Scipione
4341e994bc7SJohn Scipione	\section book_midi2apidiffs API Differences
4356ac7032dSJohn Scipione
4366ac7032dSJohn Scipione	As far as the end user is concerned, the Haiku Midi Kit is mostly the same
4376ac7032dSJohn Scipione	as the BeOS R5 kits, although there are a few small differences in the API
4386ac7032dSJohn Scipione	(mostly bug fixes):
4396ac7032dSJohn Scipione		- BMidiEndpoint::IsPersistent() always returns false.
4406ac7032dSJohn Scipione		- The B_MIDI_CHANGE_LATENCY notification is now properly sent. The Be
4416ac7032dSJohn Scipione			kit  incorrectly set be:op to B_MIDI_CHANGED_NAME, even though the
4426ac7032dSJohn Scipione			rest of the  message was properly structured.
4436ac7032dSJohn Scipione		- If creating a local endpoint fails, you can still Release() the object
4446ac7032dSJohn Scipione		  without crashing into the debugger.
4456ac7032dSJohn Scipione
4461e994bc7SJohn Scipione	\section book_midi2seealso See also
4476ac7032dSJohn Scipione
4486ac7032dSJohn Scipione	More about the Midi Kit:
4496ac7032dSJohn Scipione		- \ref Midi2Defs.h
4506ac7032dSJohn Scipione		- Be Newsletter Volume 3, Issue 47 - Motor Mix sample code
4516ac7032dSJohn Scipione		- Be Newsletter Volume 4, Issue 3 - Overview of the new kit
4524d556706SAugustin Cavalier		- <A HREF="https://haiku-os.org/documents/dev/introduction_to_midi_part_1">Newsletter
4536ac7032dSJohn Scipione		  33</A>, Introduction to MIDI, Part 1
4544d556706SAugustin Cavalier		- <A HREF="https://haiku-os.org/documents/dev/introduction_to_midi_part_2">Newsletter
4556ac7032dSJohn Scipione		  36</A>, Introduction to MIDI, Part 2
4566ac7032dSJohn Scipione		- Sample code and other goodies at the
4574d556706SAugustin Cavalier		  <A HREF="https://haiku-os.org/about/teams/midi_kit">Haiku Midi Kit team page</A>
4586ac7032dSJohn Scipione
4596ac7032dSJohn Scipione	Information about MIDI in general:
4604d556706SAugustin Cavalier		- <A HREF="https://www.midi.org">MIDI Manufacturers Association</A>
4614d556706SAugustin Cavalier		- <A HREF="https://www.borg.com/~jglatt/tutr/miditutr.htm">MIDI Tutorials</A>
4624d556706SAugustin Cavalier		- <A HREF="https://www.borg.com/~jglatt/tech/midispec.htm">MIDI Specification</A>
4634d556706SAugustin Cavalier		- <A HREF="https://www.borg.com/~jglatt/tech/midifile.htm">Standard MIDI File Format</A>
4644d556706SAugustin Cavalier		- <A HREF="https://www.io.com/~jimm/midi_ref.html">Jim Menard's MIDI Reference</A>
4656ac7032dSJohn Scipione
4666ac7032dSJohn Scipione
4674cf62172SAdrien Destugues	\defgroup network Network Kit
4684cf62172SAdrien Destugues	\brief Classes that deal with all network connections and communications.
4696ac7032dSJohn Scipione
470b1a9f638SJohn Scipione	The Haiku Network Kit consists of:
471b1a9f638SJohn Scipione	- A modular, add-ons based network stack
47295c9effdSAugustin Cavalier	- Two shared libraries, libnetwork.so and libnetapi.so
473b1a9f638SJohn Scipione	- A stack driver, acting as interface between the network stack and
47495c9effdSAugustin Cavalier	  libnetwork.so
475b1a9f638SJohn Scipione	- Basic network apps
476b1a9f638SJohn Scipione	- A modular GUI preflet
477b1a9f638SJohn Scipione
478b1a9f638SJohn Scipione	The libnet.so shared library is the way that BeOS R5 provided POSIX/BSD
479b1a9f638SJohn Scipione	API sockets to apps. Being binary compatible with BeOS R5 has made this
480b1a9f638SJohn Scipione	library implementation tedious. To counter this, the libnetapi.so shared
481b1a9f638SJohn Scipione	library was developed. It contains thin C++ classes wrapping the C
482b1a9f638SJohn Scipione	sockets POSIX/BSD API into these BNet* classes we're used under BeOS.
483b1a9f638SJohn Scipione
484b1a9f638SJohn Scipione	The stack driver is the interface between libnet.so and the real stack
485b1a9f638SJohn Scipione	behind it, hosted by the network stack kernel modules. Its purposes
486b1a9f638SJohn Scipione	include:
487b1a9f638SJohn Scipione	-# Providing sockets to file descriptors translation support
488b1a9f638SJohn Scipione	-# Providing support for select() on sockets
489b1a9f638SJohn Scipione	-# Loading the network stack on first access, and then keeping it for
490b1a9f638SJohn Scipione	   further accesses
491b1a9f638SJohn Scipione
492b1a9f638SJohn Scipione	The following diagram illustrates the network stack design on Haiku:
493b1a9f638SJohn Scipione
494b1a9f638SJohn Scipione	\image html obos_net_stack_design_1.gif
495b1a9f638SJohn Scipione
496b1a9f638SJohn Scipione	The Network Kit includes a handful of useful networking related apps
497b1a9f638SJohn Scipione	including ping, ifconfig, route, traceroute, and arp.
498b1a9f638SJohn Scipione
499b1a9f638SJohn Scipione	See the User Guide for more information about the
5004d556706SAugustin Cavalier	<a href="https://haiku-os.org/docs/userguide/en/preferences/network.html">Network preferences app</a>
501b1a9f638SJohn Scipione	included as part of the Network Kit.
502b1a9f638SJohn Scipione
503b1a9f638SJohn Scipione
5046ac7032dSJohn Scipione	\defgroup storage Storage Kit
5056ac7032dSJohn Scipione	\brief Collection of classes that deal with storing and retrieving
5066ac7032dSJohn Scipione		information from disk.
5076ac7032dSJohn Scipione
5086ac7032dSJohn Scipione
5096ac7032dSJohn Scipione	\defgroup support Support Kit
5106ac7032dSJohn Scipione	\brief Collection of utility classes that are used throughout the API.
5116ac7032dSJohn Scipione
5126ac7032dSJohn Scipione	The Support Kit provides a handy set of classes that you can use in your
5136ac7032dSJohn Scipione	applications. These classes provide:
5146ac7032dSJohn Scipione		- \b Thread \b Safety. Haiku can execute multiple threads of an
5156ac7032dSJohn Scipione			application in parallel, letting certain parts of an application
5166ac7032dSJohn Scipione			continue when one part is stalled, as well as letting an application
5176ac7032dSJohn Scipione			process multiple pieces of data at the same time on multicore or
5186ac7032dSJohn Scipione			multiprocessor systems. However, there are times when multiple
5196ac7032dSJohn Scipione			threads desire to work on the same piece of data at the same time,
5206ac7032dSJohn Scipione			potentially causing a conflict where variables or pointers are
5216ac7032dSJohn Scipione			changed by one thread causing another to execute incorrectly. To
5226ac7032dSJohn Scipione			prevent this, Haiku implements a \"locking\" mechanism, allowing one
5236ac7032dSJohn Scipione			thread to \"lock out\" other threads from executing code that might
5246ac7032dSJohn Scipione			modify the same data.
5256ac7032dSJohn Scipione		  - \b Archiving \b and \b IO. These classes allow a programmer to
5266ac7032dSJohn Scipione			convert objects into a form that can more easily be transferred to
5276ac7032dSJohn Scipione			other applications or stored to disk, as well as performing basic
5286ac7032dSJohn Scipione			input and output operations.
5296ac7032dSJohn Scipione		  - \b Memory \b Allocation. This class allows a programmer to hand off
5306ac7032dSJohn Scipione			some of the duties of memory accounting and management.
5316ac7032dSJohn Scipione		  - \b Common \b Datatypes. To avoid unnecessary duplication of code
5326ac7032dSJohn Scipione			and to make life easier for programmers, Haiku includes classes that
5336ac7032dSJohn Scipione			handle management of ordered lists and strings.
5346ac7032dSJohn Scipione
5356ac7032dSJohn Scipione	There are also a number of utility functions to time actions, play system
5366ac7032dSJohn Scipione	alert sounds, compare strings, and atomically manipulate integers. Have a
5376ac7032dSJohn Scipione	look at the overview, or go straight to the complete
5386ac7032dSJohn Scipione	\link support list of components \endlink of this kit.
5396ac7032dSJohn Scipione
5401e994bc7SJohn Scipione	\section book_overview Overview
5416ac7032dSJohn Scipione		- Thread Safety:
5426ac7032dSJohn Scipione			- BLocker provides a semaphore-like locking mechanism allowing for
5436ac7032dSJohn Scipione				recursive locks.
5446ac7032dSJohn Scipione			- BAutolock provides a simple method of automatically removing a
5456ac7032dSJohn Scipione				lock when a function ends.
5466ac7032dSJohn Scipione			- \ref TLS.h "Thread Local Storage" allows a global variable\'s
5476ac7032dSJohn Scipione				content to be sensitive to thread context.
5486ac7032dSJohn Scipione		- Archiving and IO:
5496ac7032dSJohn Scipione			- BArchivable provides an interface for \"archiving\" objects so
5506ac7032dSJohn Scipione				that they may be sent to other applications where an identical
5516ac7032dSJohn Scipione				copy will be recreated.
5526ac7032dSJohn Scipione			- BArchiver simplifies archiving of BArchivable hierarchies.
5536ac7032dSJohn Scipione			- BUnarchiver simplifies unarchiving hierarchies that have been
5546ac7032dSJohn Scipione				archived using BArchiver.
5556ac7032dSJohn Scipione			- BFlattenable provides an interface for \"flattening\" objects so
5566ac7032dSJohn Scipione				that they may be easily stored to disk.
5576ac7032dSJohn Scipione		- BDataIO provides an interface for generalized read/write streams.
5586ac7032dSJohn Scipione			- BPositionIO extends BDataIO to allow seeking within the data.
5596ac7032dSJohn Scipione			- BBufferIO creates a buffer and attaches it to a BPositionIO
5606ac7032dSJohn Scipione				stream, allowing for reduced load on the underlying stream.
5616ac7032dSJohn Scipione			- BMemoryIO allows operation on an already-existing buffer.
5626ac7032dSJohn Scipione			- BMallocIO creates and allows operation on a buffer.
5636ac7032dSJohn Scipione		- Memory Allocation:
5646ac7032dSJohn Scipione			- BBlockCache allows an application to allocate a \"pool\" of
5656ac7032dSJohn Scipione				memory blocks that the application can fetch and dispose of as
5666ac7032dSJohn Scipione				it pleases, letting the application make only a few large memory
5676ac7032dSJohn Scipione				allocations, instead of many small expensive allocations.
5686ac7032dSJohn Scipione		- Common Datatypes:
5696ac7032dSJohn Scipione			- BList allows simple ordered lists and provides common access,
5706ac7032dSJohn Scipione				modification, and comparison functions.
5716ac7032dSJohn Scipione			- BString allows strings and provides common access, modification,
5726ac7032dSJohn Scipione				and comparison functions.
5736ac7032dSJohn Scipione		- BStopWatch allows an application to measure the time an action takes.
5746ac7032dSJohn Scipione			- \ref support_globals "Global functions"
5756ac7032dSJohn Scipione			- \ref TypeConstants.h "Common types and constants"
5766ac7032dSJohn Scipione			- Error codes for all kits
5776ac7032dSJohn Scipione
5786ac7032dSJohn Scipione
5793528f5bbSJohn Scipione	\defgroup translation Translation Kit
5803528f5bbSJohn Scipione	\brief Provides a framework for converting data streams between media
5813528f5bbSJohn Scipione		formats.
5823528f5bbSJohn Scipione
5833528f5bbSJohn Scipione
58402bdb5dbSFrançois Revol	\defgroup libtranslation (libtranslation.so)
58502bdb5dbSFrançois Revol
5866ac7032dSJohn Scipione	\defgroup libbe (libbe.so)
5876ac7032dSJohn Scipione
5886ac7032dSJohn Scipione
5896ac7032dSJohn Scipione	\defgroup libroot (libroot.so)
590b966e837SAdrien Destugues	\brief Implements the C and POSIX standard libraries.
5910524a6a8Smahlzeit*/
5929d54b143SNiels Sascha Reedijk
5939889ca4aSNiels Sascha Reedijk///// Subgroups /////
5949d54b143SNiels Sascha Reedijk
5959d54b143SNiels Sascha Reedijk/*!
596dba29137Swaddlesplash	\defgroup support_globals Global functions
5979d54b143SNiels Sascha Reedijk	\ingroup support
598cc19e7c0SAlex Wilson
599dba29137Swaddlesplash	\defgroup layout Layout API
600dba29137Swaddlesplash	\brief Provides classes for automatically laying out UIs.
601cc19e7c0SAlex Wilson	\ingroup interface
6029d54b143SNiels Sascha Reedijk*/
6034466b89cSJohn Scipione
6044466b89cSJohn Scipione
6054466b89cSJohn Scipione///// Special Topics /////
6064466b89cSJohn Scipione
607aa6ef665SAugustin Cavalier/*!
6084466b89cSJohn Scipione	\defgroup drivers Device Drivers
609f943fa46SAndrew Lindesay
610f943fa46SAndrew Lindesay	\defgroup json Json Handling
611f943fa46SAndrew Lindesay	\brief Provides for parsing and writing of data in Json encoding.
612094b8dcfSNiels Sascha Reedijk
613094b8dcfSNiels Sascha Reedijk	\defgroup netservices Experimental Network Services Support
614094b8dcfSNiels Sascha Reedijk	\brief Experimental API to do higher level network requests
615094b8dcfSNiels Sascha Reedijk
616094b8dcfSNiels Sascha Reedijk	This API currently is marked as experimental. It is part of the
617094b8dcfSNiels Sascha Reedijk	<code>BPrivate::Network</code> namespace, the header files are found at
618094b8dcfSNiels Sascha Reedijk	<code>headers\\private\\netservices</code>, and you have to link your
619094b8dcfSNiels Sascha Reedijk	application to <code>libnetservices.a</code>.
620aa6ef665SAugustin Cavalier*/
621094b8dcfSNiels Sascha Reedijk
622094b8dcfSNiels Sascha Reedijk
623094b8dcfSNiels Sascha Reedijk///// Namespace Documentation /////
624094b8dcfSNiels Sascha Reedijk
625094b8dcfSNiels Sascha Reedijk
626094b8dcfSNiels Sascha Reedijk//! \brief Internal or experimental API
627094b8dcfSNiels Sascha Reedijknamespace BPrivate {
628094b8dcfSNiels Sascha Reedijk	/*!
629094b8dcfSNiels Sascha Reedijk		\brief Experimental Network Services API
630094b8dcfSNiels Sascha Reedijk
631094b8dcfSNiels Sascha Reedijk		See \ref netservices for more information.
632094b8dcfSNiels Sascha Reedijk	*/
633094b8dcfSNiels Sascha Reedijk	namespace Network {
634094b8dcfSNiels Sascha Reedijk
635094b8dcfSNiels Sascha Reedijk	}
636094b8dcfSNiels Sascha Reedijk}
637