"Array already dimensioned" if DIM Follows First Use of Array (78562)


The information in this article applies to:

  • Microsoft QuickBASIC 4.0
  • Microsoft QuickBASIC 4.0b
  • Microsoft QuickBASIC 4.5
  • Microsoft Basic Professional Development System for MS-DOS 7.0
  • Microsoft Basic Professional Development System for MS-DOS 7.1
  • Microsoft BASIC Compiler for MS-DOS and OS/2 6.0
  • Microsoft BASIC Compiler for MS-DOS and OS/2 6.0b
  • Microsoft GW-BASIC 3.2
  • Microsoft GW-BASIC 3.22
  • Microsoft GW-BASIC 3.23
This article was previously published under Q78562

SUMMARY

QB.EXE, QBX.EXE, and BC.EXE report the error "Array already dimensioned" when an array is used above the code where it is dimensioned, even if the flow of control would reach the DIM statement before reaching the use of the array. BC.EXE reports the warning "Array not dimensioned" when it encounters an array that is not dimensioned before it is used. These error messages occur regardless of whether an array is dynamic or static.

These error messages do not occur in GW-Basic programs that dimension arrays after they are used as long as the DIM statement is encountered at run-time before the usage.

MORE INFORMATION

QuickBasic analyzes array declarations differently than GW-Basic. QuickBasic analyzes explicitly- and implicitly-dimensioned arrays in one top-to-bottom pass through the source file at compile time. GW-Basic dimensions arrays in the order that they are encountered at run time.

The following code example illustrates this difference. It runs under GWBasic.EXE but not under QB.EXE, QBX.EXE, or BC.EXE: 
10 REM $DYNAMIC
20 GOSUB 50
30 A(5) = 0  ' BC.EXE reports: "Array not dimensioned"
40 END
50 DIM A(20) ' QB.EXE, QBX.EXE, BC.EXE: "Array already dimensioned"
60 RETURN
Modification Type:MinorLast Reviewed:8/16/2005
Keywords:KB78562
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