Language Elements
51
NetLinx Programming Language Reference Guide
Strings
A string is an array of characters of known length. This length may be less than the dimensioned length.
For example:
DEFINE_VARIABLE
CHAR MyString[32]
INTEGER StrLen
DEFINE_START
MyString = 'STOP'
StrLen = LENGTH_STRING(MyString)
In the example above, StrLen holds the value 4, the length of MyString. The length of MyString can
range from 0 to 32. If an attempt is made to assign a string longer than the capacity of the destination
string, the copied string is truncated to fit. The string length is implicitly set when a string literal, string
expression, or variable is assigned to the string. The function
SET_LENGTH_STRING can be used to
explicitly set the length of a string to any arbitrary length between 0 and the dimension of the character
array. Here's an example:
SET_LENGTH_STRING(MyString, 3)
This causes the contents of MyString to read 'STO', even though the character 'P' still resides in
MYSTRING[4].
String expressions
A string expression is a string enclosed in double quotes containing a series of constants and/or variables
evaluated at run-time to form a string result. String expressions can contain up to 16000 characters
consisting of string literals, variables, arrays, and ASCII values between 0 and 255. Here's an example:
CHAR StrExp[6]
StrExp = "STOP, 25, 'OFF', X"
In the example above, the string expression contains the constant STOP, the value 25, the string literal
'OFF', and the variable X. Assuming STOP is 2 and X = 5, the string expression will evaluate to "2,
25, 'OFF', 5"
.
Wide strings
A wide character string data type is provided for dealing with Unicode fonts, which use 16-bit character
codes (used for many Far-Eastern fonts) instead of the standard 8-bit codes (used with most Western
fonts). Here's a syntax sample for a wide character string:
WIDECHAR WChar[40]
The statement above declares a wide character string containing 40 elements, for a total of 80 bytes. A
wide character string can be used in the same manner as other character strings. It maintains a length
field that can be retrieved using
LENGTH_STRING and set using SET_LENGTH_STRING. Here's an
example:
WIDECHAR StrExp[6]
INTEGER StrLen
StrExp = {STOP, 500, 'OFF', X}
StrLen = LENGTH_STRING(StrExp)
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