ensure that client-side message buffer thread calls thread_init callback if/when...

[jack.git] / jack / jack.h

/*
    Copyright (C) 2001 Paul Davis
    Copyright (C) 2004 Jack O'Quin
    
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation; either version 2.1 of the License, or
    (at your option) any later version.
    
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser General Public License for more details.
    
    You should have received a copy of the GNU Lesser General Public License
    along with this program; if not, write to the Free Software 
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

*/

#ifndef __jack_h__
#define __jack_h__

#ifdef __cplusplus
extern "C" {
#endif

#include <pthread.h>

#include <jack/types.h>
#include <jack/transport.h>

/**
 * Note: More documentation can be found in jack/types.h.

 */

/*************************************************************
 * NOTE: JACK_WEAK_EXPORT ***MUST*** be used on every function
 * added to the JACK API after the 0.116.2 release.
 *************************************************************/

#ifndef JACK_WEAK_EXPORT
#ifdef __GNUC__
/* JACK_WEAK_EXPORT needs to be a macro which
   expands into a compiler directive. If non-null, the directive 
   must tell the compiler to arrange for weak linkage of 
   the symbol it used with. For this to work full may
   require linker arguments in the client as well.
*/
#define JACK_WEAK_EXPORT __attribute__((weak))
#else
/* Add other things here for non-gcc platforms */
#endif
#endif


/**
 * @defgroup ClientFunctions Creating & manipulating clients
 * @{
 */

/**
 * Open an external client session with a JACK server.  This interface
 * is more complex but more powerful than jack_client_new().  With it,
 * clients may choose which of several servers to connect, and control
 * whether and how to start the server automatically, if it was not
 * already running.  There is also an option for JACK to generate a
 * unique client name, when necessary.
 *
 * @param client_name of at most jack_client_name_size() characters.
 * The name scope is local to each server.  Unless forbidden by the
 * @ref JackUseExactName option, the server will modify this name to
 * create a unique variant, if needed.
 *
 * @param options formed by OR-ing together @ref JackOptions bits.
 * Only the @ref JackOpenOptions bits are allowed.
 *
 * @param status (if non-NULL) an address for JACK to return
 * information from the open operation.  This status word is formed by
 * OR-ing together the relevant @ref JackStatus bits.
 *
 *
 * <b>Optional parameters:</b> depending on corresponding [@a options
 * bits] additional parameters may follow @a status (in this order).
 *
 * @arg [@ref JackServerName] <em>(char *) server_name</em> selects
 * from among several possible concurrent server instances.  Server
 * names are unique to each user.  If unspecified, use "default"
 * unless \$JACK_DEFAULT_SERVER is defined in the process environment.
 *
 * @return Opaque client handle if successful.  If this is NULL, the
 * open operation failed, @a *status includes @ref JackFailure and the
 * caller is not a JACK client.
 */
jack_client_t *jack_client_open (const char *client_name,
                                 jack_options_t options,
                                 jack_status_t *status, ...);

/**
 * <b>THIS FUNCTION IS DEPRECATED AND SHOULD NOT BE USED IN
 *  NEW JACK CLIENTS</b>
 *
 */
jack_client_t *jack_client_new (const char *client_name);

/**
 * Disconnects an external client from a JACK server.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_client_close (jack_client_t *client);

/**
 * @return the maximum number of characters in a JACK client name
 * including the final NULL character.  This value is a constant.
 */
int jack_client_name_size (void);

/**
 * @return pointer to actual client name.  This is useful when @ref
 * JackUseExactName is not specified on open and @ref
 * JackNameNotUnique status was returned.  In that case, the actual
 * name will differ from the @a client_name requested.
 */
char *jack_get_client_name (jack_client_t *client);

/**
 * Load an internal client into the Jack server.
 *
 * Internal clients run inside the JACK server process.  They can use
 * most of the same functions as external clients.  Each internal
 * client must declare jack_initialize() and jack_finish() entry
 * points, called at load and unload times.  See inprocess.c for an
 * example of how to write an internal client.
 *
 * @deprecated Please use jack_internal_client_load().
 *
 * @param client_name of at most jack_client_name_size() characters.
 *
 * @param load_name of a shared object file containing the code for
 * the new client.
 *
 * @param load_init an arbitary string passed to the jack_initialize()
 * routine of the new client (may be NULL).
 *
 * @return 0 if successful.
 */
int jack_internal_client_new (const char *client_name,
                              const char *load_name,
                              const char *load_init);

/**
 * Remove an internal client from a JACK server.
 *
 * @deprecated Please use jack_internal_client_load().
 */
void jack_internal_client_close (const char *client_name);

/**
 * Tell the Jack server that the program is ready to start processing
 * audio.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_activate (jack_client_t *client);

/**
 * Tell the Jack server to remove this @a client from the process
 * graph.  Also, disconnect all ports belonging to it, since inactive
 * clients have no port connections.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_deactivate (jack_client_t *client);

/**
 * @return the pthread ID of the thread running the JACK client side
 * code.
 */
pthread_t jack_client_thread_id (jack_client_t *);

/*@}*/

/**
 * @param client pointer to JACK client structure.
 *
 * Check if the JACK subsystem is running with -R (--realtime).
 *
 * @return 1 if JACK is running realtime, 0 otherwise
 */
int jack_is_realtime (jack_client_t *client);

/**
 * @defgroup NonCallbackAPI The non-callback API
 * @{
 */

/**
 * <b>THIS FUNCTION IS DEPRECATED AND SHOULD NOT BE USED IN
 * NEW JACK CLIENTS</b>
 *
 * It should be replace by use of @ jack_cycle_wait and @ jack_cycle_signal functions.
 *
 */
jack_nframes_t jack_thread_wait (jack_client_t*, int status);

/**
 * Wait until this JACK client should process data.
 * 
 * @param client - pointer to a JACK client structure
 *
 * @return the number of frames of data to process
 */
jack_nframes_t jack_cycle_wait (jack_client_t* client);
        
/**
 * Signal next clients in the graph.
 * 
 * @param client - pointer to a JACK client structure
 * @param status - if non-zero, calling thread should exit
 */
void jack_cycle_signal (jack_client_t* client, int status);
        
/**
 * Tell the Jack server to call @a thread_callback in the RT thread.
 * Typical use are in conjunction with @a jack_cycle_wait and @ jack_cycle_signal functions.
 * The code in the supplied function must be suitable for real-time
 * execution. That means that it cannot call functions that might
 * block for a long time. This includes malloc, free, printf,
 * pthread_mutex_lock, sleep, wait, poll, select, pthread_join,
 * pthread_cond_wait, etc, etc. 
 *
 * @return 0 on success, otherwise a non-zero error code.
*/    
int jack_set_process_thread(jack_client_t* client, JackThreadCallback fun, void *arg);

/*@}*/

/**
 * @defgroup ClientCallbacks Setting Client Callbacks
 * @{
 */

/**
 * Tell JACK to call @a thread_init_callback once just after
 * the creation of the thread in which all other callbacks 
 * will be handled.
 *
 * The code in the supplied function does not need to be
 * suitable for real-time execution.
 *
 * @return 0 on success, otherwise a non-zero error code, causing JACK
 * to remove that client from the process() graph.
 */
int jack_set_thread_init_callback (jack_client_t *client,
                                   JackThreadInitCallback thread_init_callback,
                                   void *arg);

/** 
 * @param client pointer to JACK client structure.
 * @param function The jack_shutdown function pointer.
 * @param arg The arguments for the jack_shutdown function.
 *
 * Register a function (and argument) to be called if and when the
 * JACK server shuts down the client thread.  The function must
 * be written as if it were an asynchonrous POSIX signal
 * handler --- use only async-safe functions, and remember that it
 * is executed from another thread.  A typical function might
 * set a flag or write to a pipe so that the rest of the
 * application knows that the JACK client thread has shut
 * down.
 *
 * NOTE: clients do not need to call this.  It exists only
 * to help more complex clients understand what is going
 * on.  It should be called before jack_client_activate().
 * 
 * NOTE: if a client calls this AND jack_on_info_shutdown(), then
 * the event of a client thread shutdown, the callback 
 * passed to this function will not be called, and the one passed to
 * jack_on_info_shutdown() will.
 */
void jack_on_shutdown (jack_client_t *client,
                       JackShutdownCallback function, void *arg);

/**
 * @param client pointer to JACK client structure.
 * @param function The jack_shutdown function pointer.
 * @param arg The arguments for the jack_shutdown function.
 *
 * Register a function (and argument) to be called if and when the
 * JACK server shuts down the client thread.  The function must
 * be written as if it were an asynchonrous POSIX signal
 * handler --- use only async-safe functions, and remember that it
 * is executed from another thread.  A typical function might
 * set a flag or write to a pipe so that the rest of the
 * application knows that the JACK client thread has shut
 * down.
 *
 * NOTE: clients do not need to call this.  It exists only
 * to help more complex clients understand what is going
 * on.  It should be called before jack_client_activate().
 *
 * NOTE: if a client calls this AND jack_on_shutdown(), then in the
 * event of a client thread shutdown, the callback   passed to 
 * this function will be called, and the one passed to
 * jack_on_shutdown() will not.
 */
void jack_on_info_shutdown (jack_client_t *client,
                            JackInfoShutdownCallback function, void *arg) JACK_WEAK_EXPORT;

/**
 * Tell the Jack server to call @a process_callback whenever there is
 * work be done, passing @a arg as the second argument.
 *
 * The code in the supplied function must be suitable for real-time
 * execution. That means that it cannot call functions that might
 * block for a long time. This includes malloc, free, printf,
 * pthread_mutex_lock, sleep, wait, poll, select, pthread_join,
 * pthread_cond_wait, etc, etc. 
 *
 * @return 0 on success, otherwise a non-zero error code, causing JACK
 * to remove that client from the process() graph.
 */
int jack_set_process_callback (jack_client_t *client,
                               JackProcessCallback process_callback,
                               void *arg);

/**
 * Tell the Jack server to call @a freewheel_callback
 * whenever we enter or leave "freewheel" mode, passing @a
 * arg as the second argument. The first argument to the
 * callback will be non-zero if JACK is entering freewheel
 * mode, and zero otherwise.
 *
 * @return 0 on success, otherwise a non-zero error code.
 */
int jack_set_freewheel_callback (jack_client_t *client,
                                 JackFreewheelCallback freewheel_callback,
                                 void *arg);

/**
 * Tell JACK to call @a bufsize_callback whenever the size of the the
 * buffer that will be passed to the @a process_callback is about to
 * change.  Clients that depend on knowing the buffer size must supply
 * a @a bufsize_callback before activating themselves.
 *
 * @param client pointer to JACK client structure.
 * @param bufsize_callback function to call when the buffer size changes.
 * @param arg argument for @a bufsize_callback.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_set_buffer_size_callback (jack_client_t *client,
                                   JackBufferSizeCallback bufsize_callback,
                                   void *arg);

/**
 * Tell the Jack server to call @a srate_callback whenever the system
 * sample rate changes.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_set_sample_rate_callback (jack_client_t *client,
                                   JackSampleRateCallback srate_callback,
                                   void *arg);

/**
 * Tell the JACK server to call @a registration_callback whenever a
 * port is registered or unregistered, passing @a arg as a parameter.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_set_client_registration_callback (jack_client_t *,
                                           JackClientRegistrationCallback
                                           registration_callback, void *arg);
        
/**
 * Tell the JACK server to call @a registration_callback whenever a
 * port is registered or unregistered, passing @a arg as a parameter.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_set_port_registration_callback (jack_client_t *,
                                         JackPortRegistrationCallback
                                         registration_callback, void *arg);

/**
 * Tell the JACK server to call @a connect_callback whenever a
 * port is connected or disconnected, passing @a arg as a parameter.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_set_port_connect_callback (jack_client_t *,
                                    JackPortConnectCallback
                                    connect_callback, void *arg);
/**
 * Tell the JACK server to call @a graph_callback whenever the
 * processing graph is reordered, passing @a arg as a parameter.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_set_graph_order_callback (jack_client_t *,
                                   JackGraphOrderCallback graph_callback,
                                   void *);

/**
 * Tell the JACK server to call @a xrun_callback whenever there is a
 * xrun, passing @a arg as a parameter.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_set_xrun_callback (jack_client_t *,
                            JackXRunCallback xrun_callback, void *arg);

/*@}*/

/**
 * @defgroup ServerControl Controlling & querying JACK server operation
 * @{
 */

/**
 * Start/Stop JACK's "freewheel" mode.
 *
 * When in "freewheel" mode, JACK no longer waits for
 * any external event to begin the start of the next process
 * cycle. 
 *
 * As a result, freewheel mode causes "faster than realtime"
 * execution of a JACK graph. If possessed, real-time
 * scheduling is dropped when entering freewheel mode, and
 * if appropriate it is reacquired when stopping.
 * 
 * IMPORTANT: on systems using capabilities to provide real-time
 * scheduling (i.e. Linux kernel 2.4), if onoff is zero, this function
 * must be called from the thread that originally called jack_activate(). 
 * This restriction does not apply to other systems (e.g. Linux kernel 2.6 
 * or OS X).
 * 
 * @param client pointer to JACK client structure
 * @param onoff  if non-zero, freewheel mode starts. Otherwise
 *                  freewheel mode ends.
 *
 * @return 0 on success, otherwise a non-zero error code.
 */
int jack_set_freewheel(jack_client_t* client, int onoff);

/**
 * Change the buffer size passed to the @a process_callback.
 *
 * This operation stops the JACK engine process cycle, then calls all
 * registered @a bufsize_callback functions before restarting the
 * process cycle.  This will cause a gap in the audio flow, so it
 * should only be done at appropriate stopping points.
 *
 * @see jack_set_buffer_size_callback()
 *
 * @param client pointer to JACK client structure.
 * @param nframes new buffer size.  Must be a power of two.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_set_buffer_size (jack_client_t *client, jack_nframes_t nframes);

/**
 * @return the sample rate of the jack system, as set by the user when
 * jackd was started.
 */
jack_nframes_t jack_get_sample_rate (jack_client_t *);

/**
 * @return the current maximum size that will ever be passed to the @a
 * process_callback.  It should only be used *before* the client has
 * been activated.  This size may change, clients that depend on it
 * must register a @a bufsize_callback so they will be notified if it
 * does.
 *
 * @see jack_set_buffer_size_callback()
 */
jack_nframes_t jack_get_buffer_size (jack_client_t *);

/**
 * Old-style interface to become the timebase for the entire JACK
 * subsystem.
 *
 * @deprecated This function still exists for compatibility with the
 * earlier transport interface, but it does nothing.  Instead, see
 * transport.h and use jack_set_timebase_callback().
 *
 * @return ENOSYS, function not implemented.
 */
int  jack_engine_takeover_timebase (jack_client_t *);

/**
 * @return the current CPU load estimated by JACK.  This is a running
 * average of the time it takes to execute a full process cycle for
 * all clients as a percentage of the real time available per cycle
 * determined by the buffer size and sample rate.
 */
float jack_cpu_load (jack_client_t *client);
        

/*@}*/

/**
 * @defgroup PortFunctions Creating & manipulating ports
 * @{
 */

/**
 * Create a new port for the client. This is an object used for moving
 * data of any type in or out of the client.  Ports may be connected
 * in various ways.
 *
 * Each port has a short name.  The port's full name contains the name
 * of the client concatenated with a colon (:) followed by its short
 * name.  The jack_port_name_size() is the maximum length of this full
 * name.  Exceeding that will cause the port registration to fail and
 * return NULL.
 *
 * All ports have a type, which may be any non-NULL and non-zero
 * length string, passed as an argument.  Some port types are built
 * into the JACK API, like JACK_DEFAULT_AUDIO_TYPE or JACK_DEFAULT_MIDI_TYPE
 *
 * @param client pointer to JACK client structure.
 * @param port_name non-empty short name for the new port (not
 * including the leading @a "client_name:").
 * @param port_type port type name.  If longer than
 * jack_port_type_size(), only that many characters are significant.
 * @param flags @ref JackPortFlags bit mask.
 * @param buffer_size must be non-zero if this is not a built-in @a
 * port_type.  Otherwise, it is ignored.
 *
 * @return jack_port_t pointer on success, otherwise NULL.
 */
jack_port_t *jack_port_register (jack_client_t *client,
                                 const char *port_name,
                                 const char *port_type,
                                 unsigned long flags,
                                 unsigned long buffer_size);

/** 
 * Remove the port from the client, disconnecting any existing
 * connections.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_port_unregister (jack_client_t *, jack_port_t *);

/**
 * This returns a pointer to the memory area associated with the
 * specified port. For an output port, it will be a memory area
 * that can be written to; for an input port, it will be an area
 * containing the data from the port's connection(s), or
 * zero-filled. if there are multiple inbound connections, the data
 * will be mixed appropriately.  
 *
 * Do not cache the returned address across process() callbacks.
 * Port buffers have to be retrieved in each callback for proper functionning.
 */
void *jack_port_get_buffer (jack_port_t *, jack_nframes_t);

/**
 * @return the full name of the jack_port_t (including the @a
 * "client_name:" prefix).
 *
 * @see jack_port_name_size().
 */
const char *jack_port_name (const jack_port_t *port);

/**
 * @return the short name of the jack_port_t (not including the @a
 * "client_name:" prefix).
 *
 * @see jack_port_name_size().
 */
const char *jack_port_short_name (const jack_port_t *port);

/**
 * @return the @ref JackPortFlags of the jack_port_t.
 */
int jack_port_flags (const jack_port_t *port);

/**
 * @return the @a port type, at most jack_port_type_size() characters
 * including a final NULL.
 */
const char *jack_port_type (const jack_port_t *port);

/** 
 * @return TRUE if the jack_port_t belongs to the jack_client_t.
 */
int jack_port_is_mine (const jack_client_t *, const jack_port_t *port);

/** 
 * @return number of connections to or from @a port.
 *
 * @pre The calling client must own @a port.
 */
int jack_port_connected (const jack_port_t *port);

/**
 * @return TRUE if the locally-owned @a port is @b directly connected
 * to the @a port_name.
 *
 * @see jack_port_name_size()
 */
int jack_port_connected_to (const jack_port_t *port,
                            const char *port_name);

/**
 * @return a null-terminated array of full port names to which the @a
 * port is connected.  If none, returns NULL.
 *
 * The caller is responsible for calling free(3) on any non-NULL
 * returned value.
 *
 * @param port locally owned jack_port_t pointer.
 *
 * @see jack_port_name_size(), jack_port_get_all_connections()
 */   
const char **jack_port_get_connections (const jack_port_t *port);

/**
 * @return a null-terminated array of full port names to which the @a
 * port is connected.  If none, returns NULL.
 *
 * The caller is responsible for calling free(3) on any non-NULL
 * returned value.
 *
 * This differs from jack_port_get_connections() in two important
 * respects:
 *
 *     1) You may not call this function from code that is
 *          executed in response to a JACK event. For example,
 *          you cannot use it in a GraphReordered handler.
 *
 *     2) You need not be the owner of the port to get information
 *          about its connections. 
 *
 * @see jack_port_name_size()
 */   
const char **jack_port_get_all_connections (const jack_client_t *client,
                                            const jack_port_t *port);

/**
 *
 * @deprecated This function will be removed from a future version 
 * of JACK. Do not use it. There is no replacement. It has 
 * turned out to serve essentially no purpose in real-life
 * JACK clients.
 */
int  jack_port_tie (jack_port_t *src, jack_port_t *dst);

/**
 *
 * @deprecated This function will be removed from a future version 
 * of JACK. Do not use it. There is no replacement. It has 
 * turned out to serve essentially no purpose in real-life
 * JACK clients.
 */
int  jack_port_untie (jack_port_t *port);

/** 
 * @return the time (in frames) between data being available or
 * delivered at/to a port, and the time at which it arrived at or is
 * delivered to the "other side" of the port.  E.g. for a physical
 * audio output port, this is the time between writing to the port and
 * when the signal will leave the connector.  For a physical audio
 * input port, this is the time between the sound arriving at the
 * connector and the corresponding frames being readable from the
 * port.
 */
jack_nframes_t jack_port_get_latency (jack_port_t *port);

/**
 * The maximum of the sum of the latencies in every
 * connection path that can be drawn between the port and other
 * ports with the @ref JackPortIsTerminal flag set.
 */
jack_nframes_t jack_port_get_total_latency (jack_client_t *,
                                            jack_port_t *port);

/**
 * The port latency is zero by default. Clients that control
 * physical hardware with non-zero latency should call this
 * to set the latency to its correct value. Note that the value
 * should include any systemic latency present "outside" the
 * physical hardware controlled by the client. For example,
 * for a client controlling a digital audio interface connected
 * to an external digital converter, the latency setting should
 * include both buffering by the audio interface *and* the converter. 
 */
void jack_port_set_latency (jack_port_t *, jack_nframes_t);
        
/**
 * Request a complete recomputation of a port's total latency. This
 * can be called by a client that has just changed the internal
 * latency of its port using  jack_port_set_latency
 * and wants to ensure that all signal pathways in the graph
 * are updated with respect to the values that will be returned
 * by  jack_port_get_total_latency. 
 * 
 * @return zero for successful execution of the request. non-zero
 *         otherwise.
 */
int jack_recompute_total_latency (jack_client_t*, jack_port_t* port);

/**
 * Request a complete recomputation of all port latencies. This
 * can be called by a client that has just changed the internal
 * latency of its port using  jack_port_set_latency
 * and wants to ensure that all signal pathways in the graph
 * are updated with respect to the values that will be returned
 * by  jack_port_get_total_latency. It allows a client 
 * to change multiple port latencies without triggering a 
 * recompute for each change.
 * 
 * @return zero for successful execution of the request. non-zero
 *         otherwise.
 */
int jack_recompute_total_latencies (jack_client_t*);

/**
 * Modify a port's short name.  May be called at any time.  If the
 * resulting full name (including the @a "client_name:" prefix) is
 * longer than jack_port_name_size(), it will be truncated.
 *
 * @return 0 on success, otherwise a non-zero error code.
 */
int jack_port_set_name (jack_port_t *port, const char *port_name);

/**
 * Set @a alias as an alias for @a port.  May be called at any time.
 * If the alias is longer than jack_port_name_size(), it will be truncated.
 * 
 * After a successful call, and until JACK exits or
 * jack_port_unset_alias() is called, may be
 * used as a alternate name for the port.
 *
 * Ports can have up to two aliases - if both are already 
 * set, this function will return an error.
 *
 * @return 0 on success, otherwise a non-zero error code.
 */
int jack_port_set_alias (jack_port_t *port, const char *alias);

/**
 * Remove @a alias as an alias for @a port.  May be called at any time.
 * 
 * After a successful call, @a alias can no longer be 
 * used as a alternate name for the port.
 *
 * @return 0 on success, otherwise a non-zero error code.
 */
int jack_port_unset_alias (jack_port_t *port, const char *alias);

/*
 * Get any aliases known for @port.
 *
 * @return the number of aliases discovered for the port
 */
int jack_port_get_aliases (const jack_port_t *port, char* const aliases[2]);

/**
 * If @ref JackPortCanMonitor is set for this @a port, turn input
 * monitoring on or off.  Otherwise, do nothing.
 */
int jack_port_request_monitor (jack_port_t *port, int onoff);

/**
 * If @ref JackPortCanMonitor is set for this @a port_name, turn input
 * monitoring on or off.  Otherwise, do nothing.
 *
 * @return 0 on success, otherwise a non-zero error code.
 *
 * @see jack_port_name_size()
 */
int jack_port_request_monitor_by_name (jack_client_t *client,
                                       const char *port_name, int onoff);

/**
 * If @ref JackPortCanMonitor is set for a port, this function turns
 * on input monitoring if it was off, and turns it off if only one
 * request has been made to turn it on.  Otherwise it does nothing.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_port_ensure_monitor (jack_port_t *port, int onoff);

/**
 * @return TRUE if input monitoring has been requested for @a port.
 */
int jack_port_monitoring_input (jack_port_t *port);

/**
 * Establish a connection between two ports.
 *
 * When a connection exists, data written to the source port will
 * be available to be read at the destination port.
 *
 * @pre The port types must be identical.
 *
 * @pre The @ref JackPortFlags of the @a source_port must include @ref
 * JackPortIsOutput.
 *
 * @pre The @ref JackPortFlags of the @a destination_port must include
 * @ref JackPortIsInput.
 *
 * @return 0 on success, EEXIST if the connection is already made,
 * otherwise a non-zero error code
 */
int jack_connect (jack_client_t *,
                  const char *source_port,
                  const char *destination_port);

/**
 * Remove a connection between two ports.
 *
 * @pre The port types must be identical.
 *
 * @pre The @ref JackPortFlags of the @a source_port must include @ref
 * JackPortIsOutput.
 *
 * @pre The @ref JackPortFlags of the @a destination_port must include
 * @ref JackPortIsInput.
 *
 * @return 0 on success, otherwise a non-zero error code
 */
int jack_disconnect (jack_client_t *,
                     const char *source_port,
                     const char *destination_port);

/**
 * Perform the same function as jack_disconnect() using port handles
 * rather than names.  This avoids the name lookup inherent in the
 * name-based version.
 *
 * Clients connecting their own ports are likely to use this function,
 * while generic connection clients (e.g. patchbays) would use
 * jack_disconnect().
 */
int jack_port_disconnect (jack_client_t *, jack_port_t *);

/**
 * @return the maximum number of characters in a full JACK port name
 * including the final NULL character.  This value is a constant.
 *
 * A port's full name contains the owning client name concatenated
 * with a colon (:) followed by its short name and a NULL
 * character.
 */
int jack_port_name_size(void);

/**
 * @return the maximum number of characters in a JACK port type name
 * including the final NULL character.  This value is a constant.
 */
int jack_port_type_size(void);
/*@}*/

/**
 * @defgroup PortSearching Looking up ports
 * @{
 */

/**
 * @param port_name_pattern A regular expression used to select 
 * ports by name.  If NULL or of zero length, no selection based 
 * on name will be carried out.
 * @param type_name_pattern A regular expression used to select 
 * ports by type.  If NULL or of zero length, no selection based 
 * on type will be carried out.
 * @param flags A value used to select ports by their flags.  
 * If zero, no selection based on flags will be carried out.
 *
 * @return a NULL-terminated array of ports that match the specified
 * arguments.  The caller is responsible for calling free(3) any
 * non-NULL returned value.
 *
 * @see jack_port_name_size(), jack_port_type_size()
 */
const char **jack_get_ports (jack_client_t *, 
                             const char *port_name_pattern, 
                             const char *type_name_pattern, 
                             unsigned long flags);

/**
 * @return address of the jack_port_t named @a port_name.
 *
 * @see jack_port_name_size()
 */
jack_port_t *jack_port_by_name (jack_client_t *, const char *port_name);

/**
 * @return address of the jack_port_t of a @a port_id.
 */
jack_port_t *jack_port_by_id (jack_client_t *client,
                              jack_port_id_t port_id);

/*@}*/


/**
 * @defgroup TimeFunctions Handling time
 * @{
 *
 * JACK time is in units of 'frames', according to the current sample rate.
 * The absolute value of frame times is meaningless, frame times have meaning
 * only relative to each other.
 */

/**
 * @return the estimated time in frames that has passed since the JACK
 * server began the current process cycle.
 */
jack_nframes_t jack_frames_since_cycle_start (const jack_client_t *);

/**
 * @return the estimated current time in frames.
 * This function is intended for use in other threads (not the process
 * callback).  The return value can be compared with the value of
 * jack_last_frame_time to relate time in other threads to JACK time.
 */
jack_nframes_t jack_frame_time (const jack_client_t *);

/**
 * @return the precise time at the start of the current process cycle.
 * This function may only be used from the process callback, and can
 * be used to interpret timestamps generated by jack_frame_time() in
 * other threads with respect to the current process cycle.
 * 
 * This is the only jack time function that returns exact time:
 * when used during the process callback it always returns the same
 * value (until the next process callback, where it will return
 * that value + nframes, etc).  The return value is guaranteed to be
 * monotonic and linear in this fashion unless an xrun occurs.
 * If an xrun occurs, clients must check this value again, as time
 * may have advanced in a non-linear way (e.g. cycles may have been skipped).
 */
jack_nframes_t jack_last_frame_time (const jack_client_t *client);

/**
 * @return the estimated time in microseconds of the specified frame time
 */
jack_time_t jack_frames_to_time(const jack_client_t *client, jack_nframes_t);

/**
 * @return the estimated time in frames for the specified system time.
 */
jack_nframes_t jack_time_to_frames(const jack_client_t *client, jack_time_t);

/**
 * @return return JACK's current system time in microseconds,
 *         using the JACK clock source. 
 * 
 * The value returned is guaranteed to be monotonic, but not linear.
 */
jack_time_t jack_get_time();

/*@}*/

/**
 * @defgroup ErrorOutput Controlling error/information output
 */
/*@{*/

/**
 * Display JACK error message.
 *
 * Set via jack_set_error_function(), otherwise a JACK-provided
 * default will print @a msg (plus a newline) to stderr.
 *
 * @param msg error message text (no newline at end).
 */
extern void (*jack_error_callback)(const char *msg);

/**
 * Set the @ref jack_error_callback for error message display.
 *
 * The JACK library provides two built-in callbacks for this purpose:
 * default_jack_error_callback() and silent_jack_error_callback().
 */
void jack_set_error_function (void (*func)(const char *));

/**
 * Display JACK info message.
 *
 * Set via jack_set_info_function(), otherwise a JACK-provided
 * default will print @a msg (plus a newline) to stdout.
 *
 * @param msg info message text (no newline at end).
 */
extern void (*jack_info_callback)(const char *msg);

/**
 * Set the @ref jack_info_callback for info message display.
 */
void jack_set_info_function (void (*func)(const char *));
/*@}*/

/**
 * The free function to be used on memory returned by jack_port_get_connections, 
 * jack_port_get_all_connections and jack_get_ports functions.
 * This is MANDATORY on Windows when otherwise all nasty runtime version related crashes can occur.
 * Developers are strongly encouraged to use this function instead of the standard "free" function in new code.
 *
 */
void jack_free(void* ptr);

#ifdef __cplusplus
}
#endif

#endif /* __jack_h__ */