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audio.device
ADCMD_ALLOCATE
ADCMD_FINISH
ADCMD_FREE
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ADCMD_SETPREC
ADCMD_WAITCYCLE
AbortIO
BeginIO
CMD_CLEAR
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OpenDevice
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Docs » Autodocs » audio.device » OpenDevice
OpenDevice - open the audio device
error = OpenDevice("audio.device", unitNumber, iORequest, flags);
The OpenDevice routine grants access to the audio device. It takes an
I/O audio request block (iORequest) and if it can successfully open
the audio device, it loads the device pointer (io_Device) and the
allocation key (ioa_AllocKey); otherwise, it returns an error
(IOERR_OPENFAIL). OpenDevice increments the open count keeping the
device from being expunged (Expunge). If the length (ioa_Length) is
non-zero, OpenDevice tries to allocate (ADCMD_ALLOCATE) audio channels
from a array of channel combination options (ioa_Data). If the
allocation succeeds, the allocated channel combination is loaded into
the unit field (ioa_Unit); otherwise, OpenDevice returns an error
(ADIOERR_ALLOCFAILED). OpenDevice does not wait for allocation to
succeed and closes (CloseDevice) the audio device if it fails. To
allocate channels, OpenDevice also requires a properly initialized
reply port (mn_ReplyPort) with an allocated signal bit.
unitNumber- not used
iORequest - pointer to audio request block (struct IOAudio)
ln_Pri - allocation precedence (-128 thru 127), only
necessary for allocation (non-zero length)
mn_ReplyPort- pointer to message port for allocation, only
necessary for allocation (non-zero length)
ioa_AllocKey- allocation key; zero to generate new key.
Otherwise, it must be set by (or copied from I/O
block that is set by) previous OpenDevice
function or ADCMD_ALLOCATE command (non-zero
length)
ioa_Data - pointer to channel combination options (byte
array, bits 0 thru 3 correspond to channels 0
thru 3), only necessary for allocation (non-zero
length)
ioa_Length - length of the channel combination option array
(0 thru 16), zero for no allocation
flags - not used
iORequest - pointer to audio request block (struct IOAudio)
io_Device - pointer to device node if OpenDevice succeeds,
otherwise -1
io_Unit - bit map of successfully allocated channels (bits
0 thru 3 correspond to channels 0 thru 3)
io_Error - error number:
0 - no error
IOERR_OPENFAIL - open failed
ADIOERR_ALLOCFAILED - allocation failed, no open
ioa_AllocKey- allocation key, set to a unique number if passed
a zero and OpenDevice succeeds
error - copy of io_Error
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