status.i4.v = dio_is_structure_c(device_indices.i4a.r, properties.i2a.r,
					 is_structure.i4a.r, errors.i2a.r,

	This routine determines if device properties are structures.

	device_indices	device index or array of device indices
	properties	property index or array of indices
			(Note: Only reading and setting properties are
			       supported by this routine.)
			(If the first value is less than zero, all devices
			 will be requested with a property index which is
			 equal to the absolute value of this argument.)
			(constants are in 'dbprops')
	is_structure	returned logical value or array of logical values
			(TRUE -> device property is a structure,
			 FALSE -> device property is not a structure)
	errors		returned ACNET status value or array of status values
	num_devices	number of devices

	This function returns status values as follows:

	OK			success
	DIO_BADARG		invalid property or number of devices passed
	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_structure_name_c, dio_longest_structure_name, structure_field_data,
	structure_field_info, structure_size_c, dio_data_type_info_c,
	dio_dev_type, dio_device_type_c, error_in_list(_c)

	C/C++ usage:

	short	properties = -PRSET;
	short	errors[NUM_DEVICES];
	int	status;
	static const int	device_indices[NUM_DEVICES] = {177531, 177833};
	int	is_structure[NUM_DEVICES];
	int	num_devices = NUM_DEVICES;

	status = dio_is_structure_c(device_indices,&properties,is_structure,