src/libmpdclient.h

   1 /* libmpdclient
   2    (c)2003-2006 by Warren Dukes (warren.dukes@gmail.com)
   3    This project's homepage is: http://www.musicpd.org
   4
   5    Redistribution and use in source and binary forms, with or without
   6    modification, are permitted provided that the following conditions
   7    are met:
   8
   9    - Redistributions of source code must retain the above copyright
  10    notice, this list of conditions and the following disclaimer.
  11
  12    - Redistributions in binary form must reproduce the above copyright
  13    notice, this list of conditions and the following disclaimer in the
  14    documentation and/or other materials provided with the distribution.
  15
  16    - Neither the name of the Music Player Daemon nor the names of its
  17    contributors may be used to endorse or promote products derived from
  18    this software without specific prior written permission.
  19
  20    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  22    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  23    A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
  24    CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  25    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  26    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  27    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  28    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  29    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  30    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31 */
  32
  33 #ifndef LIBMPDCLIENT_H
  34 #define LIBMPDCLIENT_H
  35
  36 #ifdef WIN32
  37 #  define __W32API_USE_DLLIMPORT__ 1
  38 #endif
  39
  40 #include <sys/time.h>
  41 #include <stdarg.h>
  42 #define MPD_BUFFER_MAX_LENGTH   50000
  43 #define MPD_WELCOME_MESSAGE     "OK MPD "
  44
  45 #define MPD_ERROR_TIMEOUT       10      /* timeout trying to talk to mpd */
  46 #define MPD_ERROR_SYSTEM        11      /* system error */
  47 #define MPD_ERROR_UNKHOST       12      /* unknown host */
  48 #define MPD_ERROR_CONNPORT      13      /* problems connecting to port on host */
  49 #define MPD_ERROR_NOTMPD        14      /* mpd not running on port at host */
  50 #define MPD_ERROR_NORESPONSE    15      /* no response on attempting to connect */
  51 #define MPD_ERROR_SENDING       16      /* error sending command */
  52 #define MPD_ERROR_CONNCLOSED    17      /* connection closed by mpd */
  53 #define MPD_ERROR_ACK           18      /* ACK returned! */
  54 #define MPD_ERROR_BUFFEROVERRUN 19      /* Buffer was overrun! */
  55
  56 #define MPD_ACK_ERROR_UNK       -1
  57 #define MPD_ERROR_AT_UNK        -1
  58
  59 #define MPD_ACK_ERROR_NOT_LIST                  1
  60 #define MPD_ACK_ERROR_ARG                       2
  61 #define MPD_ACK_ERROR_PASSWORD                  3
  62 #define MPD_ACK_ERROR_PERMISSION                4
  63 #define MPD_ACK_ERROR_UNKNOWN_CMD               5
  64
  65 #define MPD_ACK_ERROR_NO_EXIST                  50
  66 #define MPD_ACK_ERROR_PLAYLIST_MAX              51
  67 #define MPD_ACK_ERROR_SYSTEM                    52
  68 #define MPD_ACK_ERROR_PLAYLIST_LOAD             53
  69 #define MPD_ACK_ERROR_UPDATE_ALREADY            54
  70 #define MPD_ACK_ERROR_PLAYER_SYNC               55
  71 #define MPD_ACK_ERROR_EXIST                     56
  72
  73 #ifdef __cplusplus
  74 extern "C" {
  75 #endif
  76
  77         typedef enum mpd_TagItems {
  78                 MPD_TAG_ITEM_ARTIST,
  79                 MPD_TAG_ITEM_ALBUM,
  80                 MPD_TAG_ITEM_TITLE,
  81                 MPD_TAG_ITEM_TRACK,
  82                 MPD_TAG_ITEM_NAME,
  83                 MPD_TAG_ITEM_GENRE,
  84                 MPD_TAG_ITEM_DATE,
  85                 MPD_TAG_ITEM_COMPOSER,
  86                 MPD_TAG_ITEM_PERFORMER,
  87                 MPD_TAG_ITEM_COMMENT,
  88                 MPD_TAG_ITEM_DISC,
  89                 MPD_TAG_ITEM_FILENAME,
  90                 MPD_TAG_NUM_OF_ITEM_TYPES
  91         } mpd_TagItems;
  92
  93         extern char *mpdTagItemKeys[MPD_TAG_NUM_OF_ITEM_TYPES];
  94
  95 /* internal stuff don't touch this struct */
  96         typedef struct _mpd_ReturnElement {
  97                 char *name;
  98                 char *value;
  99         } mpd_ReturnElement;
 100
 101 /* mpd_Connection
 102  * holds info about connection to mpd
 103  * use error, and errorStr to detect errors
 104  */
 105         typedef struct _mpd_Connection {
 106                 /* use this to check the version of mpd */
 107                 int version[3];
 108                 /* IMPORTANT, you want to get the error messages from here */
 109                 char errorStr[MPD_BUFFER_MAX_LENGTH + 1];
 110                 int errorCode;
 111                 int errorAt;
 112                 /* this will be set to MPD_ERROR_* if there is an error, 0 if not */
 113                 int error;
 114                 /* DON'T TOUCH any of the rest of this stuff */
 115                 int sock;
 116                 char buffer[MPD_BUFFER_MAX_LENGTH + 1];
 117                 int buflen;
 118                 int bufstart;
 119                 int doneProcessing;
 120                 int listOks;
 121                 int doneListOk;
 122                 int commandList;
 123                 mpd_ReturnElement *returnElement;
 124                 struct timeval timeout;
 125                 char *request;
 126         } mpd_Connection;
 127
 128 /* mpd_newConnection
 129  * use this to open a new connection
 130  * you should use mpd_closeConnection, when your done with the connection,
 131  * even if an error has occurred
 132  * _timeout_ is the connection timeout period in seconds
 133  */
 134         mpd_Connection *mpd_newConnection(const char *host, int port,
 135                                           float timeout);
 136
 137         void mpd_setConnectionTimeout(mpd_Connection * connection,
 138                                       float timeout);
 139
 140 /* mpd_closeConnection
 141  * use this to close a connection and free'ing subsequent memory
 142  */
 143         void mpd_closeConnection(mpd_Connection * connection);
 144
 145 /* mpd_clearError
 146  * clears error
 147  */
 148         void mpd_clearError(mpd_Connection * connection);
 149
 150 /* STATUS STUFF */
 151
 152 /* use these with status.state to determine what state the player is in */
 153 #define MPD_STATUS_STATE_UNKNOWN        0
 154 #define MPD_STATUS_STATE_STOP           1
 155 #define MPD_STATUS_STATE_PLAY           2
 156 #define MPD_STATUS_STATE_PAUSE          3
 157
 158 /* us this with status.volume to determine if mpd has volume support */
 159 #define MPD_STATUS_NO_VOLUME            -1
 160
 161 /* mpd_Status
 162  * holds info return from status command
 163  */
 164         typedef struct mpd_Status {
 165                 /* 0-100, or MPD_STATUS_NO_VOLUME when there is no volume support */
 166                 int volume;
 167                 /* 1 if repeat is on, 0 otherwise */
 168                 int repeat;
 169                 /* 1 if random is on, 0 otherwise */
 170                 int random;
 171                 /* playlist length */
 172                 int playlistLength;
 173                 /* playlist, use this to determine when the playlist has changed */
 174                 long long playlist;
 175                 /* use with MPD_STATUS_STATE_* to determine state of player */
 176                 int state;
 177                 /* crossfade setting in seconds */
 178                 int crossfade;
 179                 /* if a song is currently selected (always the case when state is
 180                  * PLAY or PAUSE), this is the position of the currently
 181                  * playing song in the playlist, beginning with 0
 182                  */
 183                 int song;
 184                 /* Song ID of the currently selected song */
 185                 int songid;
 186                 /* time in seconds that have elapsed in the currently playing/paused
 187                  * song
 188                  */
 189                 int elapsedTime;
 190                 /* length in seconds of the currently playing/paused song */
 191                 int totalTime;
 192                 /* current bit rate in kbs */
 193                 int bitRate;
 194                 /* audio sample rate */
 195                 unsigned int sampleRate;
 196                 /* audio bits */
 197                 int bits;
 198                 /* audio channels */
 199                 int channels;
 200                 /* 1 if mpd is updating, 0 otherwise */
 201                 int updatingDb;
 202                 /* error */
 203                 char *error;
 204         } mpd_Status;
 205
 206         void mpd_sendStatusCommand(mpd_Connection * connection);
 207
 208 /* mpd_getStatus
 209  * returns status info, be sure to free it with mpd_freeStatus()
 210  * call this after mpd_sendStatusCommand()
 211  */
 212         mpd_Status *mpd_getStatus(mpd_Connection * connection);
 213
 214 /* mpd_freeStatus
 215  * free's status info malloc'd and returned by mpd_getStatus
 216  */
 217         void mpd_freeStatus(mpd_Status * status);
 218
 219         typedef struct _mpd_Stats {
 220                 int numberOfArtists;
 221                 int numberOfAlbums;
 222                 int numberOfSongs;
 223                 unsigned long uptime;
 224                 unsigned long dbUpdateTime;
 225                 unsigned long playTime;
 226                 unsigned long dbPlayTime;
 227         } mpd_Stats;
 228
 229         void mpd_sendStatsCommand(mpd_Connection * connection);
 230
 231         mpd_Stats *mpd_getStats(mpd_Connection * connection);
 232
 233         void mpd_freeStats(mpd_Stats * stats);
 234
 235 /* SONG STUFF */
 236
 237 #define MPD_SONG_NO_TIME        -1
 238 #define MPD_SONG_NO_NUM         -1
 239 #define MPD_SONG_NO_ID          -1
 240
 241 /* mpd_Song
 242  * for storing song info returned by mpd
 243  */
 244         typedef struct _mpd_Song {
 245                 /* filename of song */
 246                 char *file;
 247                 /* artist, maybe NULL if there is no tag */
 248                 char *artist;
 249                 /* title, maybe NULL if there is no tag */
 250                 char *title;
 251                 /* album, maybe NULL if there is no tag */
 252                 char *album;
 253                 /* track, maybe NULL if there is no tag */
 254                 char *track;
 255                 /* name, maybe NULL if there is no tag; it's the name of the current
 256                  * song, f.e. the icyName of the stream */
 257                 char *name;
 258                 /* date */
 259                 char *date;
 260
 261                 /* added by qball */
 262                 /* Genre */
 263                 char *genre;
 264                 /* Composer */
 265                 char *composer;
 266                 /* Disc */
 267                 char *disc;
 268                 /* Comment */
 269                 char *comment;
 270
 271                 /* length of song in seconds, check that it is not MPD_SONG_NO_TIME  */
 272                 int time;
 273                 /* if plchanges/playlistinfo/playlistid used, is the position of the
 274                  * song in the playlist */
 275                 int pos;
 276                 /* song id for a song in the playlist */
 277                 int id;
 278         } mpd_Song;
 279
 280 /* mpd_newSong
 281  * use to allocate memory for a new mpd_Song
 282  * file, artist, etc all initialized to NULL
 283  * if your going to assign values to file, artist, etc
 284  * be sure to malloc or strdup the memory
 285  * use mpd_freeSong to free the memory for the mpd_Song, it will also
 286  * free memory for file, artist, etc, so don't do it yourself
 287  */
 288         mpd_Song *mpd_newSong(void);
 289
 290 /* mpd_freeSong
 291  * use to free memory allocated by mpd_newSong
 292  * also it will free memory pointed to by file, artist, etc, so be careful
 293  */
 294         void mpd_freeSong(mpd_Song * song);
 295
 296 /* mpd_songDup
 297  * works like strDup, but for a mpd_Song
 298  */
 299         mpd_Song *mpd_songDup(mpd_Song * song);
 300
 301 /* DIRECTORY STUFF */
 302
 303 /* mpd_Directory
 304  * used to store info fro directory (right now that just the path)
 305  */
 306         typedef struct _mpd_Directory {
 307                 char *path;
 308         } mpd_Directory;
 309
 310 /* mpd_newDirectory
 311  * allocates memory for a new directory
 312  * use mpd_freeDirectory to free this memory
 313  */
 314         mpd_Directory *mpd_newDirectory(void);
 315
 316 /* mpd_freeDirectory
 317  * used to free memory allocated with mpd_newDirectory, and it frees
 318  * path of mpd_Directory, so be careful
 319  */
 320         void mpd_freeDirectory(mpd_Directory * directory);
 321
 322 /* mpd_directoryDup
 323  * works like strdup, but for mpd_Directory
 324  */
 325         mpd_Directory *mpd_directoryDup(mpd_Directory * directory);
 326
 327 /* PLAYLISTFILE STUFF */
 328
 329 /* mpd_PlaylistFile
 330  * stores info about playlist file returned by lsinfo
 331  */
 332         typedef struct _mpd_PlaylistFile {
 333                 char *path;
 334         } mpd_PlaylistFile;
 335
 336 /* mpd_newPlaylistFile
 337  * allocates memory for new mpd_PlaylistFile, path is set to NULL
 338  * free this memory with mpd_freePlaylistFile
 339  */
 340         mpd_PlaylistFile *mpd_newPlaylistFile(void);
 341
 342 /* mpd_freePlaylist
 343  * free memory allocated for freePlaylistFile, will also free
 344  * path, so be careful
 345  */
 346         void mpd_freePlaylistFile(mpd_PlaylistFile * playlist);
 347
 348 /* mpd_playlistFileDup
 349  * works like strdup, but for mpd_PlaylistFile
 350  */
 351         mpd_PlaylistFile *mpd_playlistFileDup(mpd_PlaylistFile * playlist);
 352
 353 /* INFO ENTITY STUFF */
 354
 355 /* the type of entity returned from one of the commands that generates info
 356  * use in conjunction with mpd_InfoEntity.type
 357  */
 358 #define MPD_INFO_ENTITY_TYPE_DIRECTORY          0
 359 #define MPD_INFO_ENTITY_TYPE_SONG               1
 360 #define MPD_INFO_ENTITY_TYPE_PLAYLISTFILE       2
 361
 362 /* mpd_InfoEntity
 363  * stores info on stuff returned info commands
 364  */
 365         typedef struct mpd_InfoEntity {
 366                 /* the type of entity, use with MPD_INFO_ENTITY_TYPE_* to determine
 367                  * what this entity is (song, directory, etc...)
 368                  */
 369                 int type;
 370                 /* the actual data you want, mpd_Song, mpd_Directory, etc */
 371                 union {
 372                         mpd_Directory *directory;
 373                         mpd_Song *song;
 374                         mpd_PlaylistFile *playlistFile;
 375                 } info;
 376         } mpd_InfoEntity;
 377
 378         mpd_InfoEntity *mpd_newInfoEntity(void);
 379
 380         void mpd_freeInfoEntity(mpd_InfoEntity * entity);
 381
 382 /* INFO COMMANDS AND STUFF */
 383
 384 /* use this function to loop over after calling Info/Listall functions */
 385         mpd_InfoEntity *mpd_getNextInfoEntity(mpd_Connection * connection);
 386
 387 /* fetches the currently seeletect song (the song referenced by status->song
 388  * and status->songid*/
 389         void mpd_sendCurrentSongCommand(mpd_Connection * connection);
 390
 391 /* songNum of -1, means to display the whole list */
 392         void mpd_sendPlaylistInfoCommand(mpd_Connection * connection,
 393                                          int songNum);
 394
 395 /* songId of -1, means to display the whole list */
 396         void mpd_sendPlaylistIdCommand(mpd_Connection * connection, int songId);
 397
 398 /* use this to get the changes in the playlist since version _playlist_ */
 399         void mpd_sendPlChangesCommand(mpd_Connection * connection,
 400                                       long long playlist);
 401
 402 /**
 403  * @param connection: A valid and connected mpd_Connection.
 404  * @param playlist: The playlist version you want the diff with.
 405  * A more bandwidth efficient version of the mpd_sendPlChangesCommand.
 406  * It only returns the pos+id of the changes song.
 407  */
 408         void mpd_sendPlChangesPosIdCommand(mpd_Connection * connection,
 409                                            long long playlist);
 410
 411 /* recursivel fetches all songs/dir/playlists in "dir* (no metadata is
 412  * returned) */
 413         void mpd_sendListallCommand(mpd_Connection * connection,
 414                                     const char *dir);
 415
 416 /* same as sendListallCommand, but also metadata is returned */
 417         void mpd_sendListallInfoCommand(mpd_Connection * connection,
 418                                         const char *dir);
 419
 420 /* non-recursive version of ListallInfo */
 421         void mpd_sendLsInfoCommand(mpd_Connection * connection,
 422                                    const char *dir);
 423
 424 #define MPD_TABLE_ARTIST        0
 425 #define MPD_TABLE_ALBUM         1
 426 #define MPD_TABLE_TITLE         2
 427 #define MPD_TABLE_FILENAME      3
 428
 429         void mpd_sendSearchCommand(mpd_Connection * connection, int table,
 430                                    const char *str);
 431
 432         void mpd_sendFindCommand(mpd_Connection * connection, int table,
 433                                  const char *str);
 434
 435 /* LIST TAG COMMANDS */
 436
 437 /* use this function fetch next artist entry, be sure to free the returned
 438  * string.  NULL means there are no more.  Best used with sendListArtists
 439  */
 440         char *mpd_getNextArtist(mpd_Connection * connection);
 441
 442         char *mpd_getNextAlbum(mpd_Connection * connection);
 443
 444         char *mpd_getNextTag(mpd_Connection * connection, int table);
 445
 446 /* list artist or albums by artist, arg1 should be set to the artist if
 447  * listing albums by a artist, otherwise NULL for listing all artists or albums
 448  */
 449         void mpd_sendListCommand(mpd_Connection * connection, int table,
 450                                  const char *arg1);
 451
 452 /* SIMPLE COMMANDS */
 453
 454         void mpd_sendAddCommand(mpd_Connection * connection, const char *file);
 455
 456         void mpd_sendDeleteCommand(mpd_Connection * connection, int songNum);
 457
 458         void mpd_sendDeleteIdCommand(mpd_Connection * connection, int songNum);
 459
 460         void mpd_sendSaveCommand(mpd_Connection * connection, const char *name);
 461
 462         void mpd_sendLoadCommand(mpd_Connection * connection, const char *name);
 463
 464         void mpd_sendRmCommand(mpd_Connection * connection, const char *name);
 465
 466         void mpd_sendShuffleCommand(mpd_Connection * connection);
 467
 468         void mpd_sendClearCommand(mpd_Connection * connection);
 469
 470 /* use this to start playing at the beginning, useful when in random mode */
 471 #define MPD_PLAY_AT_BEGINNING   -1
 472
 473         void mpd_sendPlayCommand(mpd_Connection * connection, int songNum);
 474
 475         void mpd_sendPlayIdCommand(mpd_Connection * connection, int songNum);
 476
 477         void mpd_sendStopCommand(mpd_Connection * connection);
 478
 479         void mpd_sendPauseCommand(mpd_Connection * connection, int pauseMode);
 480
 481         void mpd_sendNextCommand(mpd_Connection * connection);
 482
 483         void mpd_sendPrevCommand(mpd_Connection * connection);
 484
 485         void mpd_sendMoveCommand(mpd_Connection * connection, int from, int to);
 486
 487         void mpd_sendMoveIdCommand(mpd_Connection * connection, int from,
 488                                    int to);
 489
 490         void mpd_sendSwapCommand(mpd_Connection * connection, int song1,
 491                                  int song2);
 492
 493         void mpd_sendSwapIdCommand(mpd_Connection * connection, int song1,
 494                                    int song2);
 495
 496         void mpd_sendSeekCommand(mpd_Connection * connection, int song,
 497                                  int time);
 498
 499         void mpd_sendSeekIdCommand(mpd_Connection * connection, int song,
 500                                    int time);
 501
 502         void mpd_sendRepeatCommand(mpd_Connection * connection, int repeatMode);
 503
 504         void mpd_sendRandomCommand(mpd_Connection * connection, int randomMode);
 505
 506         void mpd_sendSetvolCommand(mpd_Connection * connection,
 507                                    int volumeChange);
 508
 509 /* WARNING: don't use volume command, its depreacted */
 510         void mpd_sendVolumeCommand(mpd_Connection * connection,
 511                                    int volumeChange);
 512
 513         void mpd_sendCrossfadeCommand(mpd_Connection * connection, int seconds);
 514
 515         void mpd_sendUpdateCommand(mpd_Connection * connection, char *path);
 516
 517 /* returns the update job id, call this after a update command*/
 518         int mpd_getUpdateId(mpd_Connection * connection);
 519
 520         void mpd_sendPasswordCommand(mpd_Connection * connection,
 521                                      const char *pass);
 522
 523 /* after executing a command, when your done with it to get its status
 524  * (you want to check connection->error for an error)
 525  */
 526         void mpd_finishCommand(mpd_Connection * connection);
 527
 528 /* command list stuff, use this to do things like add files very quickly */
 529         void mpd_sendCommandListBegin(mpd_Connection * connection);
 530
 531         void mpd_sendCommandListOkBegin(mpd_Connection * connection);
 532
 533         void mpd_sendCommandListEnd(mpd_Connection * connection);
 534
 535 /* advance to the next listOk
 536  * returns 0 if advanced to the next list_OK,
 537  * returns -1 if it advanced to an OK or ACK */
 538         int mpd_nextListOkCommand(mpd_Connection * connection);
 539
 540         typedef struct _mpd_OutputEntity {
 541                 int id;
 542                 char *name;
 543                 int enabled;
 544         } mpd_OutputEntity;
 545
 546         void mpd_sendOutputsCommand(mpd_Connection * connection);
 547
 548         mpd_OutputEntity *mpd_getNextOutput(mpd_Connection * connection);
 549
 550         void mpd_sendEnableOutputCommand(mpd_Connection * connection,
 551                                          int outputId);
 552
 553         void mpd_sendDisableOutputCommand(mpd_Connection * connection,
 554                                           int outputId);
 555
 556         void mpd_freeOutputElement(mpd_OutputEntity * output);
 557
 558 /**
 559  * @param connection a #mpd_Connection
 560  *
 561  * Queries mpd for the allowed commands
 562  */
 563         void mpd_sendCommandsCommand(mpd_Connection * connection);
 564 /**
 565  * @param connection a #mpd_Connection
 566  *
 567  * Queries mpd for the not allowed commands
 568  */
 569         void mpd_sendNotCommandsCommand(mpd_Connection * connection);
 570
 571 /**
 572  * @param connection a #mpd_Connection
 573  *
 574  * returns the next supported command.
 575  *
 576  * @returns a string, needs to be free'ed
 577  */
 578         char *mpd_getNextCommand(mpd_Connection * connection);
 579
 580 /**
 581  * @param connection a MpdConnection
 582  * @param path  the path to the playlist.
 583  *
 584  * List the content, with full metadata, of a stored playlist.
 585  *
 586  */
 587         void mpd_sendListPlaylistInfoCommand(mpd_Connection * connection,
 588                                              char *path);
 589 /**
 590  * @param connection a MpdConnection
 591  * @param path  the path to the playlist.
 592  *
 593  * List the content of a stored playlist.
 594  *
 595  */
 596         void mpd_sendListPlaylistCommand(mpd_Connection * connection,
 597                                          char *path);
 598
 599 /**
 600  * @param connection a #mpd_Connection
 601  * @param exact if to match exact
 602  *
 603  * starts a search, use mpd_addConstraintSearch to add
 604  * a constraint to the search, and mpd_commitSearch to do the actual search
 605  */
 606         void mpd_startSearch(mpd_Connection * connection, int exact);
 607 /**
 608  * @param connection a #mpd_Connection
 609  * @param field
 610  * @param name
 611  *
 612  */
 613         void mpd_addConstraintSearch(mpd_Connection * connection, int field,
 614                                      char *name);
 615 /**
 616  * @param connection a #mpd_Connection
 617  *
 618  */
 619         void mpd_commitSearch(mpd_Connection * connection);
 620
 621 /**
 622  * @param connection a #mpd_Connection
 623  * @param field The field to search
 624  *
 625  * starts a search for fields... f.e. get a list of artists would be:
 626  * mpd_startFieldSearch(connection, MPD_TAG_ITEM_ARTIST);
 627  * mpd_commitSearch(connection);
 628  *
 629  * or get a list of artist in genre "jazz" would be:
 630  * @code
 631  * mpd_startFieldSearch(connection, MPD_TAG_ITEM_ARTIST);
 632  * mpd_addConstraintSearch(connection, MPD_TAG_ITEM_GENRE, "jazz")
 633  * mpd_commitSearch(connection);
 634  * @endcode
 635  *
 636  * mpd_startSearch will return  a list of songs (and you need mpd_getNextInfoEntity)
 637  * this one will return a list of only one field (the field specified with field) and you need
 638  * mpd_getNextTag to get the results
 639  */
 640         void mpd_startFieldSearch(mpd_Connection * connection, int field);
 641 #ifdef __cplusplus
 642 }
 643 #endif
 644 #endif