Lines Matching defs:*
0 /* ladspa.h
3 Linux Audio Developer's Simple Plugin API Version 1.1[LGPL].
4 Copyright (C) 2000-2002 Richard W.E. Furse, Paul Barton-Davis,
5 Stefan Westerfeld.
7 This library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public License
9 as published by the Free Software Foundation; either version 2.1 of
10 the License, or (at your option) any later version.
12 This library is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public
18 License along with this library; if not, write to the Free Software
19 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
20 USA. */
22 #ifndef LADSPA_INCLUDED
23 #define LADSPA_INCLUDED
25 #define LADSPA_VERSION "1.1"
26 #define LADSPA_VERSION_MAJOR 1
27 #define LADSPA_VERSION_MINOR 1
29 #ifdef __cplusplus
30 extern "C" {
31 #endif
35 /* Overview:
37 There is a large number of synthesis packages in use or development
38 on the Linux platform at this time. This API (`The Linux Audio
39 Developer's Simple Plugin API') attempts to give programmers the
40 ability to write simple `plugin' audio processors in C/C++ and link
41 them dynamically (`plug') into a range of these packages (`hosts').
42 It should be possible for any host and any plugin to communicate
43 completely through this interface.
45 This API is deliberately short and simple. To achieve compatibility
46 with a range of promising Linux sound synthesis packages it
47 attempts to find the `greatest common divisor' in their logical
48 behaviour. Having said this, certain limiting decisions are
49 implicit, notably the use of a fixed type (LADSPA_Data) for all
50 data transfer and absence of a parameterised `initialisation'
51 phase. See below for the LADSPA_Data typedef.
53 Plugins are expected to distinguish between control and audio
54 data. Plugins have `ports' that are inputs or outputs for audio or
55 control data and each plugin is `run' for a `block' corresponding
56 to a short time interval measured in samples. Audio data is
57 communicated using arrays of LADSPA_Data, allowing a block of audio
58 to be processed by the plugin in a single pass. Control data is
59 communicated using single LADSPA_Data values. Control data has a
60 single value at the start of a call to the `run()' or `run_adding()'
61 function, and may be considered to remain this value for its
62 duration. The plugin may assume that all its input and output ports
63 have been connected to the relevant data location (see the
64 `connect_port()' function below) before it is asked to run.
66 Plugins will reside in shared object files suitable for dynamic
67 linking by dlopen() and family. The file will provide a number of
68 `plugin types' that can be used to instantiate actual plugins
69 (sometimes known as `plugin instances') that can be connected
70 together to perform tasks.
72 This API contains very limited error-handling. */
76 /* Fundamental data type passed in and out of plugin. This data type
77 is used to communicate audio samples and control values. It is
78 assumed that the plugin will work sensibly given any numeric input
79 value although it may have a preferred range (see hints below).
81 For audio it is generally assumed that 1.0f is the `0dB' reference
82 amplitude and is a `normal' signal level. */
84 typedef float LADSPA_Data;
88 /* Special Plugin Properties:
90 Optional features of the plugin type are encapsulated in the
91 LADSPA_Properties type. This is assembled by ORing individual
92 properties together. */
94 typedef int LADSPA_Properties;
96 /* Property LADSPA_PROPERTY_REALTIME indicates that the plugin has a
97 real-time dependency (e.g. listens to a MIDI device) and so its
98 output must not be cached or subject to significant latency. */
99 #define LADSPA_PROPERTY_REALTIME 0x1
101 /* Property LADSPA_PROPERTY_INPLACE_BROKEN indicates that the plugin
102 may cease to work correctly if the host elects to use the same data
103 location for both input and output (see connect_port()). This
104 should be avoided as enabling this flag makes it impossible for
105 hosts to use the plugin to process audio `in-place.' */
106 #define LADSPA_PROPERTY_INPLACE_BROKEN 0x2
108 /* Property LADSPA_PROPERTY_HARD_RT_CAPABLE indicates that the plugin
109 is capable of running not only in a conventional host but also in a
110 `hard real-time' environment. To qualify for this the plugin must
111 satisfy all of the following:
113 (1) The plugin must not use malloc(), free() or other heap memory
114 management within its run() or run_adding() functions. All new
115 memory used in run() must be managed via the stack. These
116 restrictions only apply to the run() function.
118 (2) The plugin will not attempt to make use of any library
119 functions with the exceptions of functions in the ANSI standard C
120 and C maths libraries, which the host is expected to provide.
122 (3) The plugin will not access files, devices, pipes, sockets, IPC
123 or any other mechanism that might result in process or thread
124 blocking.
126 (4) The plugin will take an amount of time to execute a run() or
127 run_adding() call approximately of form (A+B*SampleCount) where A
128 and B depend on the machine and host in use. This amount of time
129 may not depend on input signals or plugin state. The host is left
130 the responsibility to perform timings to estimate upper bounds for
131 A and B. */
132 #define LADSPA_PROPERTY_HARD_RT_CAPABLE 0x4
134 #define LADSPA_IS_REALTIME(x) ((x) & LADSPA_PROPERTY_REALTIME)
135 #define LADSPA_IS_INPLACE_BROKEN(x) ((x) & LADSPA_PROPERTY_INPLACE_BROKEN)
136 #define LADSPA_IS_HARD_RT_CAPABLE(x) ((x) & LADSPA_PROPERTY_HARD_RT_CAPABLE)
140 /* Plugin Ports:
142 Plugins have `ports' that are inputs or outputs for audio or
143 data. Ports can communicate arrays of LADSPA_Data (for audio
144 inputs/outputs) or single LADSPA_Data values (for control
145 input/outputs). This information is encapsulated in the
146 LADSPA_PortDescriptor type which is assembled by ORing individual
147 properties together.
149 Note that a port must be an input or an output port but not both
150 and that a port must be a control or audio port but not both. */
152 typedef int LADSPA_PortDescriptor;
154 /* Property LADSPA_PORT_INPUT indicates that the port is an input. */
155 #define LADSPA_PORT_INPUT 0x1
157 /* Property LADSPA_PORT_OUTPUT indicates that the port is an output. */
158 #define LADSPA_PORT_OUTPUT 0x2
160 /* Property LADSPA_PORT_CONTROL indicates that the port is a control
161 port. */
162 #define LADSPA_PORT_CONTROL 0x4
164 /* Property LADSPA_PORT_AUDIO indicates that the port is a audio
165 port. */
166 #define LADSPA_PORT_AUDIO 0x8
168 #define LADSPA_IS_PORT_INPUT(x) ((x) & LADSPA_PORT_INPUT)
169 #define LADSPA_IS_PORT_OUTPUT(x) ((x) & LADSPA_PORT_OUTPUT)
170 #define LADSPA_IS_PORT_CONTROL(x) ((x) & LADSPA_PORT_CONTROL)
171 #define LADSPA_IS_PORT_AUDIO(x) ((x) & LADSPA_PORT_AUDIO)
175 /* Plugin Port Range Hints:
177 The host may wish to provide a representation of data entering or
178 leaving a plugin (e.g. to generate a GUI automatically). To make
179 this more meaningful, the plugin should provide `hints' to the host
180 describing the usual values taken by the data.
182 Note that these are only hints. The host may ignore them and the
183 plugin must not assume that data supplied to it is meaningful. If
184 the plugin receives invalid input data it is expected to continue
185 to run without failure and, where possible, produce a sensible
186 output (e.g. a high-pass filter given a negative cutoff frequency
187 might switch to an all-pass mode).
189 Hints are meaningful for all input and output ports but hints for
190 input control ports are expected to be particularly useful.
192 More hint information is encapsulated in the
193 LADSPA_PortRangeHintDescriptor type which is assembled by ORing
194 individual hint types together. Hints may require further
195 LowerBound and UpperBound information.
197 All the hint information for a particular port is aggregated in the
198 LADSPA_PortRangeHint structure. */
200 typedef int LADSPA_PortRangeHintDescriptor;
202 /* Hint LADSPA_HINT_BOUNDED_BELOW indicates that the LowerBound field
203 of the LADSPA_PortRangeHint should be considered meaningful. The
204 value in this field should be considered the (inclusive) lower
205 bound of the valid range. If LADSPA_HINT_SAMPLE_RATE is also
206 specified then the value of LowerBound should be multiplied by the
207 sample rate. */
208 #define LADSPA_HINT_BOUNDED_BELOW 0x1
210 /* Hint LADSPA_HINT_BOUNDED_ABOVE indicates that the UpperBound field
211 of the LADSPA_PortRangeHint should be considered meaningful. The
212 value in this field should be considered the (inclusive) upper
213 bound of the valid range. If LADSPA_HINT_SAMPLE_RATE is also
214 specified then the value of UpperBound should be multiplied by the
215 sample rate. */
216 #define LADSPA_HINT_BOUNDED_ABOVE 0x2
218 /* Hint LADSPA_HINT_TOGGLED indicates that the data item should be
219 considered a Boolean toggle. Data less than or equal to zero should
220 be considered `off' or `false,' and data above zero should be
221 considered `on' or `true.' LADSPA_HINT_TOGGLED may not be used in
222 conjunction with any other hint except LADSPA_HINT_DEFAULT_0 or
223 LADSPA_HINT_DEFAULT_1. */
224 #define LADSPA_HINT_TOGGLED 0x4
226 /* Hint LADSPA_HINT_SAMPLE_RATE indicates that any bounds specified
227 should be interpreted as multiples of the sample rate. For
228 instance, a frequency range from 0Hz to the Nyquist frequency (half
229 the sample rate) could be requested by this hint in conjunction
230 with LowerBound = 0 and UpperBound = 0.5. Hosts that support bounds
231 at all must support this hint to retain meaning. */
232 #define LADSPA_HINT_SAMPLE_RATE 0x8
234 /* Hint LADSPA_HINT_LOGARITHMIC indicates that it is likely that the
235 user will find it more intuitive to view values using a logarithmic
236 scale. This is particularly useful for frequencies and gains. */
237 #define LADSPA_HINT_LOGARITHMIC 0x10
239 /* Hint LADSPA_HINT_INTEGER indicates that a user interface would
240 probably wish to provide a stepped control taking only integer
241 values. Any bounds set should be slightly wider than the actual
242 integer range required to avoid floating point rounding errors. For
243 instance, the integer set {0,1,2,3} might be described as [-0.1,
244 3.1]. */
245 #define LADSPA_HINT_INTEGER 0x20
247 /* The various LADSPA_HINT_HAS_DEFAULT_* hints indicate a `normal'
248 value for the port that is sensible as a default. For instance,
249 this value is suitable for use as an initial value in a user
250 interface or as a value the host might assign to a control port
251 when the user has not provided one. Defaults are encoded using a
252 mask so only one default may be specified for a port. Some of the
253 hints make use of lower and upper bounds, in which case the
254 relevant bound or bounds must be available and
255 LADSPA_HINT_SAMPLE_RATE must be applied as usual. The resulting
256 default must be rounded if LADSPA_HINT_INTEGER is present. Default
257 values were introduced in LADSPA v1.1. */
258 #define LADSPA_HINT_DEFAULT_MASK 0x3C0
260 /* This default values indicates that no default is provided. */
261 #define LADSPA_HINT_DEFAULT_NONE 0x0
263 /* This default hint indicates that the suggested lower bound for the
264 port should be used. */
265 #define LADSPA_HINT_DEFAULT_MINIMUM 0x40
267 /* This default hint indicates that a low value between the suggested
268 lower and upper bounds should be chosen. For ports with
269 LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.75 +
270 log(upper) * 0.25). Otherwise, this should be (lower * 0.75 + upper
271 * 0.25). */
272 #define LADSPA_HINT_DEFAULT_LOW 0x80
274 /* This default hint indicates that a middle value between the
275 suggested lower and upper bounds should be chosen. For ports with
276 LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.5 +
277 log(upper) * 0.5). Otherwise, this should be (lower * 0.5 + upper *
278 0.5). */
279 #define LADSPA_HINT_DEFAULT_MIDDLE 0xC0
281 /* This default hint indicates that a high value between the suggested
282 lower and upper bounds should be chosen. For ports with
283 LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.25 +
284 log(upper) * 0.75). Otherwise, this should be (lower * 0.25 + upper
285 * 0.75). */
286 #define LADSPA_HINT_DEFAULT_HIGH 0x100
288 /* This default hint indicates that the suggested upper bound for the
289 port should be used. */
290 #define LADSPA_HINT_DEFAULT_MAXIMUM 0x140
292 /* This default hint indicates that the number 0 should be used. Note
293 that this default may be used in conjunction with
294 LADSPA_HINT_TOGGLED. */
295 #define LADSPA_HINT_DEFAULT_0 0x200
297 /* This default hint indicates that the number 1 should be used. Note
298 that this default may be used in conjunction with
299 LADSPA_HINT_TOGGLED. */
300 #define LADSPA_HINT_DEFAULT_1 0x240
302 /* This default hint indicates that the number 100 should be used. */
303 #define LADSPA_HINT_DEFAULT_100 0x280
305 /* This default hint indicates that the Hz frequency of `concert A'
306 should be used. This will be 440 unless the host uses an unusual
307 tuning convention, in which case it may be within a few Hz. */
308 #define LADSPA_HINT_DEFAULT_440 0x2C0
310 #define LADSPA_IS_HINT_BOUNDED_BELOW(x) ((x) & LADSPA_HINT_BOUNDED_BELOW)
311 #define LADSPA_IS_HINT_BOUNDED_ABOVE(x) ((x) & LADSPA_HINT_BOUNDED_ABOVE)
312 #define LADSPA_IS_HINT_TOGGLED(x) ((x) & LADSPA_HINT_TOGGLED)
313 #define LADSPA_IS_HINT_SAMPLE_RATE(x) ((x) & LADSPA_HINT_SAMPLE_RATE)
314 #define LADSPA_IS_HINT_LOGARITHMIC(x) ((x) & LADSPA_HINT_LOGARITHMIC)
315 #define LADSPA_IS_HINT_INTEGER(x) ((x) & LADSPA_HINT_INTEGER)
317 #define LADSPA_IS_HINT_HAS_DEFAULT(x) ((x) & LADSPA_HINT_DEFAULT_MASK)
318 #define LADSPA_IS_HINT_DEFAULT_MINIMUM(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \
319 == LADSPA_HINT_DEFAULT_MINIMUM)
320 #define LADSPA_IS_HINT_DEFAULT_LOW(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \
321 == LADSPA_HINT_DEFAULT_LOW)
322 #define LADSPA_IS_HINT_DEFAULT_MIDDLE(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \
323 == LADSPA_HINT_DEFAULT_MIDDLE)
324 #define LADSPA_IS_HINT_DEFAULT_HIGH(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \
325 == LADSPA_HINT_DEFAULT_HIGH)
326 #define LADSPA_IS_HINT_DEFAULT_MAXIMUM(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \
327 == LADSPA_HINT_DEFAULT_MAXIMUM)
328 #define LADSPA_IS_HINT_DEFAULT_0(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \
329 == LADSPA_HINT_DEFAULT_0)
330 #define LADSPA_IS_HINT_DEFAULT_1(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \
331 == LADSPA_HINT_DEFAULT_1)
332 #define LADSPA_IS_HINT_DEFAULT_100(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \
333 == LADSPA_HINT_DEFAULT_100)
334 #define LADSPA_IS_HINT_DEFAULT_440(x) (((x) & LADSPA_HINT_DEFAULT_MASK) \
335 == LADSPA_HINT_DEFAULT_440)
337 typedef struct _LADSPA_PortRangeHint {
339 /* Hints about the port. */
340 LADSPA_PortRangeHintDescriptor HintDescriptor;
342 /* Meaningful when hint LADSPA_HINT_BOUNDED_BELOW is active. When
343 LADSPA_HINT_SAMPLE_RATE is also active then this value should be
344 multiplied by the relevant sample rate. */
345 LADSPA_Data LowerBound;
347 /* Meaningful when hint LADSPA_HINT_BOUNDED_ABOVE is active. When
348 LADSPA_HINT_SAMPLE_RATE is also active then this value should be
349 multiplied by the relevant sample rate. */
350 LADSPA_Data UpperBound;
352 } LADSPA_PortRangeHint;
356 /* Plugin Handles:
358 This plugin handle indicates a particular instance of the plugin
359 concerned. It is valid to compare this to NULL (0 for C++) but
360 otherwise the host should not attempt to interpret it. The plugin
361 may use it to reference internal instance data. */
363 typedef void * LADSPA_Handle;
367 /* Descriptor for a Type of Plugin:
369 This structure is used to describe a plugin type. It provides a
370 number of functions to examine the type, instantiate it, link it to
371 buffers and workspaces and to run it. */
373 typedef struct _LADSPA_Descriptor {
375 /* This numeric identifier indicates the plugin type
376 uniquely. Plugin programmers may reserve ranges of IDs from a
377 central body to avoid clashes. Hosts may assume that IDs are
378 below 0x1000000. */
379 unsigned long UniqueID;
381 /* This identifier can be used as a unique, case-sensitive
382 identifier for the plugin type within the plugin file. Plugin
383 types should be identified by file and label rather than by index
384 or plugin name, which may be changed in new plugin
385 versions. Labels must not contain white-space characters. */
386 const char * Label;
388 /* This indicates a number of properties of the plugin. */
389 LADSPA_Properties Properties;
391 /* This member points to the null-terminated name of the plugin
392 (e.g. "Sine Oscillator"). */
393 const char * Name;
395 /* This member points to the null-terminated string indicating the
396 maker of the plugin. This can be an empty string but not NULL. */
397 const char * Maker;
399 /* This member points to the null-terminated string indicating any
400 copyright applying to the plugin. If no Copyright applies the
401 string "None" should be used. */
402 const char * Copyright;
404 /* This indicates the number of ports (input AND output) present on
405 the plugin. */
406 unsigned long PortCount;
408 /* This member indicates an array of port descriptors. Valid indices
409 vary from 0 to PortCount-1. */
410 const LADSPA_PortDescriptor * PortDescriptors;
412 /* This member indicates an array of null-terminated strings
413 describing ports (e.g. "Frequency (Hz)"). Valid indices vary from
414 0 to PortCount-1. */
415 const char * const * PortNames;
417 /* This member indicates an array of range hints for each port (see
418 above). Valid indices vary from 0 to PortCount-1. */
419 const LADSPA_PortRangeHint * PortRangeHints;
421 /* This may be used by the plugin developer to pass any custom
422 implementation data into an instantiate call. It must not be used
423 or interpreted by the host. It is expected that most plugin
424 writers will not use this facility as LADSPA_Handle should be
425 used to hold instance data. */
426 void * ImplementationData;
428 /* This member is a function pointer that instantiates a plugin. A
429 handle is returned indicating the new plugin instance. The
430 instantiation function accepts a sample rate as a parameter. The
431 plugin descriptor from which this instantiate function was found
432 must also be passed. This function must return NULL if
433 instantiation fails.
435 Note that instance initialisation should generally occur in
436 activate() rather than here. */
437 LADSPA_Handle (*instantiate)(const struct _LADSPA_Descriptor * Descriptor,
438 unsigned long SampleRate);
440 /* This member is a function pointer that connects a port on an
441 instantiated plugin to a memory location at which a block of data
442 for the port will be read/written. The data location is expected
443 to be an array of LADSPA_Data for audio ports or a single
444 LADSPA_Data value for control ports. Memory issues will be
445 managed by the host. The plugin must read/write the data at these
446 locations every time run() or run_adding() is called and the data
447 present at the time of this connection call should not be
448 considered meaningful.
450 connect_port() may be called more than once for a plugin instance
451 to allow the host to change the buffers that the plugin is
452 reading or writing. These calls may be made before or after
453 activate() or deactivate() calls.
455 connect_port() must be called at least once for each port before
456 run() or run_adding() is called. When working with blocks of
457 LADSPA_Data the plugin should pay careful attention to the block
458 size passed to the run function as the block allocated may only
459 just be large enough to contain the block of samples.
461 Plugin writers should be aware that the host may elect to use the
462 same buffer for more than one port and even use the same buffer
463 for both input and output (see LADSPA_PROPERTY_INPLACE_BROKEN).
464 However, overlapped buffers or use of a single buffer for both
465 audio and control data may result in unexpected behaviour. */
466 void (*connect_port)(LADSPA_Handle Instance,
467 unsigned long Port,
468 LADSPA_Data * DataLocation);
470 /* This member is a function pointer that initialises a plugin
471 instance and activates it for use. This is separated from
472 instantiate() to aid real-time support and so that hosts can
473 reinitialise a plugin instance by calling deactivate() and then
474 activate(). In this case the plugin instance must reset all state
475 information dependent on the history of the plugin instance
476 except for any data locations provided by connect_port() and any
477 gain set by set_run_adding_gain(). If there is nothing for
478 activate() to do then the plugin writer may provide a NULL rather
479 than an empty function.
481 When present, hosts must call this function once before run() (or
482 run_adding()) is called for the first time. This call should be
483 made as close to the run() call as possible and indicates to
484 real-time plugins that they are now live. Plugins should not rely
485 on a prompt call to run() after activate(). activate() may not be
486 called again unless deactivate() is called first. Note that
487 connect_port() may be called before or after a call to
488 activate(). */
489 void (*activate)(LADSPA_Handle Instance);
491 /* This method is a function pointer that runs an instance of a
492 plugin for a block. Two parameters are required: the first is a
493 handle to the particular instance to be run and the second
494 indicates the block size (in samples) for which the plugin
495 instance may run.
497 Note that if an activate() function exists then it must be called
498 before run() or run_adding(). If deactivate() is called for a
499 plugin instance then the plugin instance may not be reused until
500 activate() has been called again.
502 If the plugin has the property LADSPA_PROPERTY_HARD_RT_CAPABLE
503 then there are various things that the plugin should not do
504 within the run() or run_adding() functions (see above). */
505 void (*run)(LADSPA_Handle Instance,
506 unsigned long SampleCount);
508 /* This method is a function pointer that runs an instance of a
509 plugin for a block. This has identical behaviour to run() except
510 in the way data is output from the plugin. When run() is used,
511 values are written directly to the memory areas associated with
512 the output ports. However when run_adding() is called, values
513 must be added to the values already present in the memory
514 areas. Furthermore, output values written must be scaled by the
515 current gain set by set_run_adding_gain() (see below) before
516 addition.
518 run_adding() is optional. When it is not provided by a plugin,
519 this function pointer must be set to NULL. When it is provided,
520 the function set_run_adding_gain() must be provided also. */
521 void (*run_adding)(LADSPA_Handle Instance,
522 unsigned long SampleCount);
524 /* This method is a function pointer that sets the output gain for
525 use when run_adding() is called (see above). If this function is
526 never called the gain is assumed to default to 1. Gain
527 information should be retained when activate() or deactivate()
528 are called.
530 This function should be provided by the plugin if and only if the
531 run_adding() function is provided. When it is absent this
532 function pointer must be set to NULL. */
533 void (*set_run_adding_gain)(LADSPA_Handle Instance,
534 LADSPA_Data Gain);
536 /* This is the counterpart to activate() (see above). If there is
537 nothing for deactivate() to do then the plugin writer may provide
538 a NULL rather than an empty function.
540 Hosts must deactivate all activated units after they have been
541 run() (or run_adding()) for the last time. This call should be
542 made as close to the last run() call as possible and indicates to
543 real-time plugins that they are no longer live. Plugins should
544 not rely on prompt deactivation. Note that connect_port() may be
545 called before or after a call to deactivate().
547 Deactivation is not similar to pausing as the plugin instance
548 will be reinitialised when activate() is called to reuse it. */
549 void (*deactivate)(LADSPA_Handle Instance);
551 /* Once an instance of a plugin has been finished with it can be
552 deleted using the following function. The instance handle passed
553 ceases to be valid after this call.
555 If activate() was called for a plugin instance then a
556 corresponding call to deactivate() must be made before cleanup()
557 is called. */
558 void (*cleanup)(LADSPA_Handle Instance);
560 } LADSPA_Descriptor;
564 /* Accessing a Plugin: */
566 /* The exact mechanism by which plugins are loaded is host-dependent,
567 however all most hosts will need to know is the name of shared
568 object file containing the plugin types. To allow multiple hosts to
569 share plugin types, hosts may wish to check for environment
570 variable LADSPA_PATH. If present, this should contain a
571 colon-separated path indicating directories that should be searched
572 (in order) when loading plugin types.
574 A plugin programmer must include a function called
575 "ladspa_descriptor" with the following function prototype within
576 the shared object file. This function will have C-style linkage (if
577 you are using C++ this is taken care of by the `extern "C"' clause
578 at the top of the file).
580 A host will find the plugin shared object file by one means or
581 another, find the ladspa_descriptor() function, call it, and
582 proceed from there.
584 Plugin types are accessed by index (not ID) using values from 0
585 upwards. Out of range indexes must result in this function
586 returning NULL, so the plugin count can be determined by checking
587 for the least index that results in NULL being returned. */
589 const LADSPA_Descriptor * ladspa_descriptor(unsigned long Index);
591 /* Datatype corresponding to the ladspa_descriptor() function. */
592 typedef const LADSPA_Descriptor *
593 (*LADSPA_Descriptor_Function)(unsigned long Index);
597 #ifdef __cplusplus
599 #endif
601 #endif /* LADSPA_INCLUDED */
603 /* EOF */