Language Elements
45
NetLinx Programming Language Reference Guide
 Declare a DEVLEV array whose maximum length is determined by the number of elements in
the initialization array on the right-hand side.
DEVLEV DLName[ ] = {{Dev1,Level1}, {Dev2,Level2}, ...}

Use MAXLEN to specify the maximum length of the array.
DEVLEV DLName[MAXLEN] = {{Dev1,Level1}, {Dev2,Level2}, ...}
In either case, the number of elements in the initialization array determines the effective length of the
array. That value can be determined at run-time by calling
LENGTH_ARRAY. The maximum length
available for a
DEVLEV array can be determined by calling MAX_LENGTH_ARRAY.
The individual elements of a level array can be referenced by their defined names (
Dev1, Level1,
Dev2, Level2, etc.) or alternatively, by using array notation with the device-level array name. For
example, the 3rd element in the device-level array,
MyDLSet, would be referenced by MyDLSet[3].
Furthermore, since a
DEVLEV array is an array of DEVLEV structures, DEVLEV members can be
referenced using the dot operator notation such as
MyDLSet[3].Device or MyDLSet[1].Level.
The index of the last member of the array for which an event notification was received can be determined
by calling
GET_LAST(MyDLSet). This is useful for determining which device and level in an array is
referenced to in a particular notification message.
Variables
NetLinx provides support for several different types of variables distinguished by attributes, such as:
 Scope
 Constancy
 Persistence
Scope
Scope is a term used in reference to program variables that describe where in the program they can be
accessed. There are two types:
 Local scope: a variable can only be accessed in the subroutine or method that it is declared.
 Global scope: a variable can be accessed anywhere in the program.
Scope differentiates the two basic classes of NetLinx variables:
 Local variable: a variable declared within a subroutine or function whose scope is limited to
that subroutine or function.
 Global variable: a variable declared in the DEFINE_VARIABLE section; its scope extends
throughout the module in which it is declared.
Local variables
Local variables are restricted in scope to the statement block in which they are declared. A statement
block is one or more NetLinx statements enclosed in a pair of braces, like the blocks following
subroutines, functions, conditionals, loops, waits, and so on. Local variables must be declared
immediately after the opening brace of a block but before the first executable statement. To provide
compatibility with the Axcess language, local variables may be declared right before the opening brace
for
DEFINE_CALL declarations only. For example, both formats shown below are legal in the NetLinx
language:
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