Echelon Neuron C - Manual (Page 194)

174 Network Variable, Configuration Property, and Message Tag Declarations
device_properties { property-reference-list };
property-reference-list :
property-reference-list , property-reference
property-reference
property-reference :
property-identifier [= initializer ] [ range-mod ]
property-identifier [ range-mod ] [= initializer ]
range-mod : range_mod_string ( concatenated-string-constant )
property-identifier :
cpnv-prop-ident
cp-family-prop-ident
cpnv-prop-ident : identifier [ constant-array-index-expr ]
identifier
cp-family-prop-ident : identifier
The device property list begins with the device_properties keyword. It then
contains a list of property references, separated by commas. Each property
reference must be the name of a previously declared CP family or the name of a
previously declared configuration network variable. If the network variable is an
array, and a single element of that array is to be used as a property for the
device, specify that element with an index expression (such as var[4]) in the
device_properties clause. On the other hand, if the property is itself the
entire network variable array, specify just the array name without an index
expression (such as var, where var is declared as an array) in the
device_properties clause.
Following the
property-identifier , there can be an optional initializer , and an
optional range-mod . These optional elements can occur in either order if both are
given. If present, the instantiation initializer for a CP family member overrides
any initializer provided at the time of declaration of the CP family; thus, using
this mechanism, some CP family members can be initialized specially, with the
remaining CP family members having a more generic initial value. If a network
variable is initialized in multiple places (in other words, in its declaration as well
as in its use in a property list), the initializations must be identical in type and
value.
The device property list appears at file scope. This is the same level as a function
declaration, a task declaration, or a global data declaration.
A Neuron C program can have multiple device property lists. These lists are
merged together by the compiler to create one combined device property list.
This feature is provided for modularity in the program (different modules can
specify certain properties for the device, but the list is combined by the compiler).
However, you cannot have more than one configuration property of any given
SCPT or UCPT type that applies to the device.
If two separate modules specify a particular configuration of the same type in the
device property lists, this situation causes a compilation error.
Finally, each property instantiation can have a range-modification string
following the property identifier. The range-modification string works identically
to the range-mod described Configuration Property Modifiers (cp-modifiers) on