Docs » Autodocs » audio.device » ADCMD_FREE
ADCMD_FREE -- free audio channels for allocation
ADCMD_FREE is a command for multiple audio channels. For each
selected channel (io_Unit), if the allocation key (ioa_AllocKey) is
correct, ADCMD_FREE does the following:
. restores the channel to a known state (CMD_RESET),
. changes the channels allocation key, and
. makes the channel available for re-allocation.
. If the channel is locked (ADCMD_LOCK) ADCMD_FREE unlocks it and
clears the bit for the channel (io_Unit) in the lock I/O request.
If the lock I/O request has no channel bits set ADCMD_FREE replies
the lock I/O request, and
. checks if there are allocation requests (ADCMD_ALLOCATE) waiting
for the channel.
Otherwise, ADCMD_FREE returns an error (ADIOERR_NOALLOCATION).
ADCMD_FREE is synchronous and only replies (mn_ReplyPort) if the quick
flag (IOF_QUICK) is clear. Do not use ADCMD_FREE in interrupt code.
mn_ReplyPort- pointer to message port that receives I/O request
if the quick flag (IOF_QUICK) is clear
io_Device - pointer to device node, must be set by (or copied from
I/O block set by) OpenDevice function
io_Unit - bit map of channels to free (bits 0 thru 3 correspond to
channels 0 thru 3)
io_Command - command number for ADCMD_FREE
io_Flags - flags, must be cleared if not used:
IOF_QUICK - (CLEAR) reply I/O request
ioa_AllocKey- allocation key, must be set by (or copied from I/O block
set by) OpenDevice function or ADCMD_ALLOCATE command
io_Unit - bit map of channels successfully freed (bits 0 thru 3
correspond to channels 0 thru 3)
io_Error - error number:
0 - no error
ADIOERR_NOALLOCATION - allocation key (ioa_AllocKey)
does not match key for channel