3 playlistfs \- playlist file system
19 implements an audio player which plays files from a built-in play list.
20 The player is controlled through three files, usually mounted at
24 for controlling play: start, stop, pause, skip, etc.;
26 for controlling the playout volume; and
28 for controlling the play list itself.
30 All three files can be written to control the player and read to obtain player
33 When read, the files report the current status of the player, volume and playlist,
34 respectively. End of file is indicated by a read that returns zero bytes, as usual.
35 However, in all three files, subsequent read operations will block until the status
36 of the file changes and then report the changed state. When the changed state has
37 been read, another end-of-file indication is given, after which another read
38 can be issued to wait for state changes.
42 file returns strings of the form `\f2cmd n\fP'
52 is an index (or offset) into the playlist; indices start at zero.
54 The commands that can be written to
56 take the same form; however, the index is an optional argument. If the
57 index is omitted, the current value is used. The commands are
65 starts playing at the index.
67 stops playing. If an index is given, the current index is set to it and
68 can be used in future commands.
72 interrupt and continue play, respectively. The index argument is always ignored and
73 the whole command is ignored if the state in which they occur does not
76 adds the argument to the current index (adds one if no argument is given)
77 and starts play at that index, stopping current play, if necessary.
81 return strings of the form
82 .BR "`volume \f2n\fP'" ,
85 is a number or, if there is more than one channel, a quoted set of numbers, between 0
86 (minimum) and 100 (maximum).
93 file is an append-only file which accepts lines with one or two fields
94 per line (parsed using
96 The first, compulsory, field is a file name, the optional second argument
97 may contain a reference to, or a description of, the item, for instance in a graphical
100 is append-only, individual lines cannot be removed. However, the playlist
101 can be cleared by opening the file with the
103 flag. A process that has
105 open while the file is truncated will receive an error on the next read with
108 .IR "reading past eof" .
109 When this error occurs, clients can seek to the beginning of the file and reread its contents.
113 puts itself in the background. When called with the
115 flag, it posts a mountable file descriptor in
116 .BR /srv/playlist.\f2postname\fP .
119 flag can be used to specify a mount point other than
127 for format detection and conversion to pcm.
129 .BR /srv/playlistfs.\f2user\fP :
132 mountable file descriptor used by juke(7).
143 .B /sys/src/games/music/playlistfs