Labels & Line Numbers Must Be Unique, Even Across Subprograms (20540)
This article was previously published under Q20540
SUMMARY
This information applies to Microsoft QuickBASIC Versions 1.00, 1.00a,
1.00b, Microsoft BASIC Compiler Version 1.00, and Microsoft BASIC
Interpreter Versions 2.00, 2.10, and 3.00 for the Apple Macintosh.
All labels and line numbers used in interpreted program must be
unique. No two labels or line numbers can be the same when a program
is interpreted, even if they are in separate subprograms.
BASIC interpreter Version 2.00 does not properly warn you about
duplicate labels, and incorrect branching can occur when using
duplicate labels in Version 2.00.
BASIC interpreter Versions 2.10 and 3.00 and the interpreter in
QuickBASIC properly stop the program with an error message "Duplicate
Label" when duplicate labels are found at run time.
The BASIC compiler Version 1.00 and the QuickBASIC Compiler treat line
numbers and labels locally and will not generate an error message if
there are duplicates in separate subprograms. This is an undocumented
difference between compiled and interpreted programs.
| Modification Type: |
Minor |
Last Reviewed: |
1/8/2003 |
| Keywords: |
KB20540 |
|