Rockwell Automation 2708-NBD VBASIC Language Development Kit - Manual (Page 56)

A-B VBASIC and Visual BASIC
Appendix B
Differences Between
B–8
may not return the same file numbers, even in identical programs. Just
because a file number is unassigned does not imply that a new file can be
created. There is a maximum number of files which can exist, open or not.
See the Limits section for specifics on A-B VBASIC file and device
limitations.
IF NumFilesOpen < 15 THEN NextFileNum = FREEFILE
FUNCTION name[(parameterlist)][STATIC]
Declares the name, the parameters, and the code that form the body of a
FUNCTION. The appearance of a FUNCTION’s name on the right side of an
= or in an argument list, is considered to be a call to that function, with or
without an “(argument list)”. Do not use FUNCTION procedures that
perform I/O in I/O statements.
CurrTime$ = GetTime$
FUNCTION GetTime$()
GetTime$ = TIME$
END FUNCTION
GET [#]filenumber[,[recordnumber][,variable]]
Reads data from a file in memory into a variable. All 3 items after GET are
required, however the record number can be consecutive commas as in, GET
#1,,V$. See the chapter on Special Devices for details about input from
specific devices. FIELD is not supported, use TYPE..END TYPE.
TYPE EmpType
Badge AS STRING * 8
Name AS STRING * 25
END TYPE
DIM SHARED Emp AS EmpType
OPEN “EMPLOYEE” FOR RANDOM AS #1 LEN = LEN(Emp)
Rec = 0
DO WHILE NOT EOF(1)
Rec = Rec + 1
GET #1, Rec, Emp
IF Emp.Badge = BadgeInput$ THEN Found = TRUE: EXIT DO
LOOP
CLOSE #1
GOSUB {linelabel | linenumber}....RETURN
Branches to and returns from a sub–routine. Linelabel on RETURNs are not
supported in A-B VBASIC. BASIC’s SUB and FUNCTION procedures
provide a more well–structured alternative to GOSUB...RETURN
subroutines.
DO
CurrTime$ = LEFT$(GetTime$,4)
IF CurrTime$ > OldTime$ THEN
GOSUB UpdateTime
OldTime$ = CurrTime$