status.i4.v = dio_emc_to_device_index(emcs.u1a.r, device_indices.i4a.r,
					      errors.i2a.r [,num_devices.i4.r])

	This routine retrieves the device index for a given Event Message
	Code (EMC).  If "num_devices" is specified, device indices for a
	list of EMCs can be retrieved.

	emcs		EMC or an array of EMCs
			(each EMC should be LEN_EMC bytes int)
	device_indices	returned device index or array of device indices
	errors		returned ACNET status value or array of status values
	[num_devices]	number of devices (default is 1)

	This function returns status values as follows:

	OK			success
	DIO_MEMFAIL		memory allocation failure
	negative value		ACNET format error indicating overall failure
	positive value		number of devices in error indicating partial

	This function requires the following include files:

	cnsparam_h, diolib_h, acnet_errors_h

	Related functions:

	dio_dev_emc, dio_emc_type_c, dio_delete_all_emc_info, error_in_list(_c)

	C/C++ usage:

	static unsigned char	emcs[NUM_DEVICES][LEN_EMC] =
	short		errors[NUM_DEVICES];
	int		status;
	int		device_indices[NUM_DEVICES];
	int		num_devices = NUM_DEVICES;

	status = dio_emc_to_device_index((unsigned char *) emcs,device_indices,