AMX NETLINX PROGRAMMING LANGUAGE, Manual

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Language Elements
49 NetLinx Programming Language Reference Guide
stored. With persistent variables, the new NetLinx program can be downloaded and all of the presets
remain intact.
When a new NetLinx program is downloaded to the Master, the Master iterates through all non-volatile
variables from the new program looking for persistent ones. When it finds a persistent variable in the
new program, it searches the old programs persistent variable space for the "same variable". When it
finds the same variable, the value of the new variable is set to the same value as the old programs
variable. It is important to note what is considered to be the "same variable". The master identifies the
"same variable" by verifying for duplicity the following:
Variable name
Variable source location
Variable type
Therefore, in order for persistence to function properly, the name, type, and file declared in must be the
same as the previously downloaded NetLinx program. If you changed any of the three, the new persistent
variable will not be set with the old variable’s value.
Constants
Constants are defined in the
DEFINE_CONSTANT
section. The scope of a constant extends throughout
the module or program in which it is defined. The name assigned to a constant must be unique among all
other identifiers defined in the module or program. The syntax is:
DEFINE_CONSTANT
<constant name> = <constant expression>
Constants may be assigned expressions that consist only of other constants and operators. Variables are
not allowed in constant expressions. An example is:
VALUE_OFFSET = 500
VALUE1 = VALUE_ 1
STR1 = 'This is a string constant.'
Constants can be used anywhere that a numeric or string constant is allowed. The value assigned to a
constant can be specified in one of the formats listed in the following table.
Valid Formats for Constants
Type Format Example
Decimal Integer 0000 1500
Hexadecimal Integer $000 $DE60
Floating Point 000.0 924.5
Exponential Notation 0.0e0 1.5e-12
Character 'c' or <char code> 'R' or 255
String Literal 'ssss' 'Reverse'