ALSA Library Reference Manual

Digital audio(PCM) interface

SND_PCM_OPEN_PLAYBACK
SND_PCM_OPEN_CAPTURE
SND_PCM_OPEN_DUPLEX
SND_PCM_OPEN_NONBLOCK

misc

Plug-In interface (ala C++)

Plug-In constructors

basic I/O

conversion plugins

Loopback interface