Audio
Line and Control Queries
The mixer
services provide functions for determining information about audio lines,
audio-line controls, and control details. The services also provide functions
for setting control details.
You can use
the mixerGetLineInfo
function to retrieve information about a specified audio line. This function
fills the MIXERLINE
structure for a specified source audio line, destination audio line, or line
identifier. The structure includes the destination line number, the number of
channels in the audio line, as well as a short and a long name for the audio
line.
The mixerGetLineControls function retrieves general
information about one or more controls associated with an audio line. This
function fills the MIXERLINECONTROLS structure with information about the specified
control or controls. You can use mixerGetLineControls to retrieve
control properties for one of the following:
All controls for a specified
source line
A specified control for a
specified source line
The first control of a specific
class for a specified source line
The mixerGetControlDetails function retrieves
properties of a single control associated with an audio line. This function
fills the MIXERCONTROLDETAILS
structure with the current values for a control.
The mixerSetControlDetails function uses the contents
of the MIXERCONTROLDETAILS structure to set the properties of the
specified control. You must ensure that all members of this structure are
filled before you call mixerSetControlDetails.