Echelon Neuron C - Manual (Page 181)

Neuron C Reference Guide 161
Network Variable Declarations Syntax
The complete syntax for declaring a network variable is one of the following:
network input | output [ netvar-modifier ]
[ class ] type [ connection-info ] [config_prop [ cp-modifiers ]]
identifier [= initial-value ] [ nv-property-list ] ;
network input | output [ netvar-modifier ]
[ class ] type [ connection-info ] [config_prop [ cp-modifiers ]]
identifier [ array-bound ] [= initializer-list ] [ nv-property-list ] ;
The brackets around array-bound are shown in bold type. The brackets do not, in
this case, indicate an optional field. They are a required part of the syntax of
declaring an array, and must be entered into the program code.
The maximum number of network variables available to a device depends on the
target chip type, firmware version, and the device development platform used.
For all chips, firmware, and development platforms, each element of a network
variable array counts as a separate network variable relative to the maximum
number and configuration network variables count towards that maximum
number.
Network Variable Modifiers (netvar-modifier)
One or more of the following optional modifiers can be included in the declaration
of each network variable:
sync | synchronized
Specifies that all values assigned to this network variable
must be propagated, and in their original order. Mutually
exclusive with the polled modifier.
polled Specifies that the value of the output network variable is
to be sent
only in response to a poll request from a device
that reads this network variable. When this keyword is
omitted, the value is propagated over the network every
time the variable is assigned a value and also when
polled. Mutually exclusive with the sync modifier.
Normally only used for output network variables. Can be
used with input network variables in model files.
changeable_type Specifies that the network variable type can be changed
at runtime. If either the sync or polled keyword is used
(these two keywords are mutually exclusive) along with
the changeable_type keyword, then the changeable_type
keyword must follow the other keyword. For more
information on changeable type network variables, see
Changeable Type Network Variables in How Devices
Communicate Using Network Variables in the Neuron C
Programmer’s Guide .
The changeable_type keyword requires the program ID to
be specified, and requires the Changeable Interface flag to
be set in that program ID. A compilation error occurs
otherwise.