Analog Devices VISUALDSP++ 3.5 Manual page 206

C/C++ Run-Time Model and Environment
If the device is not successfully registered, a negative value is returned.
Reasons for failure include, but are not limited to:
• The DeviceID is the same as another device, already registered
• There are no more spaces left in the device registry table
• The DeviceID is less than zero
• Some of the function pointers are NULL
• The device's
Once a device is registered, it can be made the default device, using the
following function:
void set_default_io_device(int);
The user passes the
retrieving the current default device:
int get_default_io_device(void);
The default device is used by
function passes the open request to the
fopen()
device indicated by
( ) returned by the
dfid
devices may simultaneously have other files open which use the same iden-
tifier. An open file is uniquely identified by the combination of
and .
dfid
The function records the
fopen()
file table, and allocates its own internal
operations on the file reads, writes, seeks and close —use this
retrieve the
DeviceID
device's primitive functions, passing the
Once a file has been opened by
get_default_io_device()
1-168
routine returned a failure result
init()
. There is a corresponding function for
DeviceID
fopen()
get_default_io_device()
function is private to the device; other
open()
DeviceID
—and thus direct the request to the appropriate
fopen()
is irrelevant to that file.
VisualDSP++ 3.5 C/C++ Compiler and Library Manual
when a file is first opened. The
function of the
open()
. The device file identifier
and in the global open
dfid
to this combination. All future
fid
along with other parameters.
dfid
, the current value of
for ADSP-219x DSPs
DeviceID
to
fid