ibdev() is used to obtain a device descriptor, which can then be used by other functions in the library. The argument board_index specifies which GPIB interface board the device is connected to. The pad and sad arguments specify the GPIB address of the device to be opened (see ibpad() and ibsad()). The timeout for io operations is specified by timeout (see ibtmo()). If send_eoi is nonzero, then the EOI line will be asserted with the last byte sent during writes (see ibeot()). Finally, the eos argument specifies the end-of-string character and whether or not its reception should terminate reads (see ibeos()).