Inside Macintosh: Sound Manager

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Gestalt Selector and Response Bits

You can pass the gestaltSoundAttr selector to the Gestalt function to determine information about the sound input capabilities of a Macintosh computer.

CONST
    gestaltSoundAttr                    = 'snd ';       {sound attributes selector}

The Gestalt function returns information by setting or clearing bits in the response parameter. The bits relevant to the Sound Input Manager are defined by constants:

CONST
    gestaltSoundIOMgrPresent            = 3;        {sound input routines available}
    gestaltBuiltInSoundInput            = 4;        {built-in input hw available}
    gestaltHasSoundInputDevice          = 5;        {sound input device available}
    gestaltPlayAndRecord                = 6;        {built-in hw can play while recording}
    gestalt16BitSoundIO                 = 7;        {built-in hw can handle 16-bit data}
    gestaltStereoInput                  = 8;        {built-in hw can record stereo sounds}
    gestaltLineLevelInput               = 9;        {built-in input hw needs line level}

Constant descriptions

gestaltSoundIOMgrPresent
Set if the Sound Input Manager is available.
gestaltBuiltInSoundInput
Set if a built-in sound input device is available.
gestaltHasSoundInputDevice
Set if a sound input device is available. This device can be either built-in or external.
gestaltPlayAndRecord
Set if the built-in sound hardware is able to play and record sounds simultaneously. If this bit is clear, the built-in sound hardware can either play or record, but not do both at once. This bit is valid only if the gestaltBuiltInSoundInput bit is set, and it applies only to any built-in sound input and output hardware.
gestalt16BitSoundIO
Set if the built-in sound hardware is able to play and record 16-bit samples. This indicates that built-in hardware necessary to handle 16-bit data is available.
gestaltStereoInput
Set if the built-in sound hardware can record stereo sounds.
gestaltLineLevelInput
Set if the built-in sound input port requires line level input.

For complete information about the Gestalt function, see the chapter "Gestalt Manager" in Inside Macintosh: Operating System Utilities .

© 1998 Apple Computer, Inc.

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