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)
Содержание NETLINX PROGRAMMING LANGUAGE
Страница 15: ...Table of Contents xiii NetLinx Programming Language Reference Guide...
Страница 16: ...xiv NetLinx Programming Language Reference Guide Table of Contents...
Страница 18: ...Introduction 2 NetLinx Programming Language Reference Guide...
Страница 76: ...Language Elements 60 NetLinx Programming Language Reference Guide...
Страница 106: ...Combining Devices Levels and Channels 90 NetLinx Programming Language Reference Guide...
Страница 112: ...Master To Master M2M 96 NetLinx Programming Language Reference Guide...
Страница 114: ...Mainline 98 NetLinx Programming Language Reference Guide FIG 1 Message and Mainline Processing in the NetLinx System...
Страница 182: ...Reserved Identifiers 166 NetLinx Programming Language Reference Guide...
Страница 204: ...NetLinx UniCode Functions 188 NetLinx Programming Language Reference Guide...
Страница 244: ...Appendix B Glossary 228 NetLinx Programming Language Reference Guide...
Страница 245: ...Appendix B Glossary 229 NetLinx Programming Language Reference Guide...