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Q41446: QB 2.x/3.00 Example to Load DOS Directory Listing into Array

Article: Q41446
Product(s): See article
Version(s): 2.00 2.01 3.00
Operating System(s): MS-DOS
Keyword(s): ENDUSER | | mspl13_basic
Last Modified: 8-MAR-1989

This article discusses methods to put a disk directory listing into a
string array in QuickBASIC Version 2.00, 2.01, or 3.00. (This
information was prepared because the FILES statement in QuickBASIC
only outputs to the screen, and not to a file or variables.)

Example 1 shows a simple method to SHELL to the DIR command, redirect
the output to a file, and input from the file into string variables.

Example 2 shows how to invoke MS-DOS operating-system functions to
retrieve a disk directory into string variables. This example uses the
CALL INT86 statement to invoke MS-DOS interrupt hex 21 with the
following functions:

   hex 1A (SetDTA)

   hex 4E (FindFirst)

   hex 4F (FindNext)

This example of using CALL INT86 applies to Microsoft QuickBASIC
Versions 2.00, 2.01, and 3.00. For instructions for later versions of
QuickBASIC, please refer to a separate article in this KnowledgeBase
by querying for the following keywords:

   INTERRUPT and FINDFIRST and FINDNEXT

Example 1 (the simplest technique) is as follows:

' Works in QuickBASIC 2.00, 2.01, 3.00, 4.00, 4.00b, 4.50, and
' BASIC Compiler 6.00 and 6.00b. Add line numbers to work in
' GW-BASIC 3.20, 3.22, or 3.23.
nf = 200   ' Handles directory listing up to 200 lines.
DIM buffer$(nf)
INPUT "Enter Search Path: ", path$   ' Enter path such as c:
SHELLSTRING$ = "dir " + path$ + " >dirfile.dat"
SHELL SHELLSTRING$   ' SHELL to the MS-DOS DIRectory command.
OPEN "dirfile.dat" FOR INPUT AS #1
pntr% = 0
WHILE NOT EOF(1) AND pntr% < nf
  pntr% = pntr% + 1
  INPUT #1, buffer$(pntr%)  ' Inputs one directory line at a time.
  PRINT buffer$(pntr%)
WEND
CLOSE #1
KILL "dirfile.dat"   ' Deletes the temporary file.
END

Example 2 is as follows:

To use the DIRLIST.BAS program below in QuickBASIC Version 3.00, you
must first make a User Library that contains INT86.OBJ, or else you
can link DIRLIST.OBJ directly to INT86.OBJ. In QuickBASIC Versions
2.00 and 2.01, you would use USERLIB.OBJ instead of INT86.OBJ in the
two alternatives below. The following are the two choices:

1. The following command makes USERLIB.EXE:

      BUILDLIB INT86;

   You can then invoke the QB.EXE editor with the /L option to
   access the User Library that contains the INT86 routine:

      QB DIRLIST.BAS /L USERLIB.EXE

   When you choose the EXE output option in the Compile... window, the
   resulting .EXE program requires the presence of USERLIB.EXE.

2. You can compile and link as follows:

      QB DIRLIST.BAS;
      LINK DIRLIST.OBJ+INT86.OBJ;

The following is the Source Code for DIRLIST.BAS:

DIM InArray%(9), OutArray%(9)
AX% = 0: DX% = 3: DS% = 8: CX% = 2  ' -- Register locations
DTA$ = SPACE$(43)                   ' -- DTA Buffer size
Path$ = "*.*" + CHR$(0)             ' -- Search path, plus null byte

REM -- Find Segment and Offset for the DTA (Disk Transfer Area)
CALL PTR86(Seg1%, Off1%, VARPTR(DTA$))

REM -- The real Offset for the string DTA$ is found by using the
REM    SADD function.
Off1% = SADD(DTA$)

REM -- Set the DTA with Interrupt Hex 21, and Function Hex 1A
InArray%(AX%) = &H1A00
InArray%(DX%) = Off1%
InArray%(DS%) = Seg1%
CALL INT86(&H21, VARPTR(InArray%(0)), VARPTR(OutArray%(0)))

REM -- Find the Segment and Offset for the Search Path
CALL PTR86(Seg1%, Off1%, VARPTR(Path$))

REM -- Real Offset is found by using the SADD function
Off1% = SADD(Path$)

REM -- Find the first file with Interrupt Hex 21, Function Hex 4E
InArray%(AX%) = &H4E00
InArray%(CX%) = 22
InArray%(DX%) = Off1%
InArray%(DS%) = Seg1%
CALL INT86(&H21, VARPTR(InArray%(0)), VARPTR(OutArray%(0)))

REM -- Stay in while loop until
REM    18 = No more files
REM     3 = Invalid search path -OR- no files found
WHILE (OutArray%(AX%) <> 18) AND (OutArray%(AX%) <> 3)
   a% = CVI(MID$(DTA$, 27, 2))  ' -- Low word of file size
   b% = CVI(MID$(DTA$, 29, 2))  ' -- High word of file size
   IF a% < 0 THEN               ' -- Calculate size relative to
      d! = 65536 + a%           '    Low word
   ELSE
      d! = a%
   END IF
   IF b% < 0 THEN               ' -- Calculate size with High word
      d! = d! + (65536 * (65536 + b%))
   ELSE
      d! = d! + (65536 * b%)
   END IF
   PRINT RIGHT$(DTA$, 13);      ' -- Print file name
   PRINT "  ";
   PRINT d!                     '    and file size
   MID$(DTA$, 31, 13) = SPACE$(13) ' -- Blank out current name
   InArray%(AX%) = &H4F00       ' Function Hex 4F - Find Next File
   CALL INT86(&H21, VARPTR(InArray%(0)), VARPTR(OutArray%(0)))
WEND
END

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