AGetSystemChannelGain(3X)

NAME

AGetSystemChannelGain − get system or monitor channel gain

SYNOPSIS

#include <Alib.h> void
AGetSystemChannelGain (

Audio ∗ audio,

ASystemGainType gain_type,

AChType channel,

AGainDB ∗ gain_return,

long ∗ status_return );

DESCRIPTION

AGetSystemChannelGain() Returns the current monitor or system gain.

audio the Audio structure associated with this connection.

gain_type the type of operation: ASGTPlay, ASGTRecord, or ASGTMonitor. If this field is set to ASGTMonitor, the channel specification must be ACTMono.

channel the type of channel: ACTMono, ACTLeft, or ACTRight. If gain_type is ASGTMonitor, this field must be ACTMono.

gain_return receives the returned gain value (decimal value).

status_return receives the returned status of the operation, unless this parameter is passed in as a NULL pointer. If status_return is set to NULL, Alib will do the error handling.

ERRORS

If status_return is not set to NULL, it can return one of the following values:

0 AENoError No error - the call completed successfully.

2 AEBadAudio The audio structure is invalid. A pointer to a valid audio structure may be missing (use AOpenAudio() to get a valid pointer).

3 AEBadValue The channel or gain_type parameter contains in incorrect value.

EXAMPLE

The following example gets the system monitor gain.

Audio ∗ audio; /∗ audio connection ∗/

ASystemGainType ∗ sgtype; /∗ type of operation ∗/

AChType ∗ chtype; /∗ type of channel ∗/

AGainDB chgain_ret; /∗ gain value∗/

long status; /∗ error status ∗/
.
.
.

/∗ get monitor gain ∗/

sgtype = ASGTMonitor;

chtype = ACTMono;

ASetSystemChannelGain(audio, sgtype, chtype, &chgain_ret, &status);

NOTE

In order to ensure that the compiler finds the Audio Library (libAlib.sl) and the Alib.h header file, you must add the following switches:

-L /opt/audio/lib
-I/opt/audio/include

DEPENDENCIES

This function belongs to the Audio Library of functions that manage connections to an audio server. The audio server must run on a system that has audio hardware. To find out whether or not your system has audio hardware, refer to Using the Audio Developer’s Kit or the online help for the Audio control panel. For information about the audio capabilities of a particular system use the online example audioinfo.c.

AUTHOR

AGetSystemChannelGain() was developed by HP.

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