Omega Speaker Systems 8 Channel Thermocouple USB Data Acquisition Module TC-08 - Manual (Page 19)

Technical reference 15
3.3.2 New USB mode and legacy mode
3.3.2.1 usb_tc08_open_unit
short usb_tc08_open_unit (void)
This routine returns a valid handle to the USB TC-08 if the driver successfully opens it.
If the routine fails, see the error code explanations in the
usb_tc08_get_last_error
section. If you wish to use more than one USB TC-08, call this routine once for each
unit connected to the PC. The function will return 0 if there are no more units found.
The driver is thread-safe and will not allow access to a single unit from more than one
application. If, therefore,
usb_tc08_open_unit does not find a unit, check that
other applications are not using the USB TC-08. This includes applications on other
user accounts on the same computer, where fast user switching is supported.
Note: The usb_tc08_open_unit function provides a simple way to open USB TC-08
units. However, the function call locks up the calling thread until the attached USB
TC-08 unit has been fully enumerated. If a single-threaded application needs to
perform concurrent processing, such as displaying a progress bar, use
usb_tc08_open_unit_async .
Arguments None