Q67379: How to Use CALL INTERRUPT to Detect If SHARE.EXE Is Loaded

Article: Q67379
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | B_BASICCOM | mspl13_basic
Last Modified: 5-DEC-1990

SHARE.EXE provides file sharing and locking to MS-DOS versions 3.00
and later. To determine whether SHARE.EXE is currently loaded, you can
make a call to the MS-DOS interrupt, &H2F (2F hex). You should load
the ax register with &H1000 before the CALL INTERRUPT statement. After
the call, the ax register will return with the value &H00FF (ff hex)
if SHARE.EXE is loaded.

This information applies to Microsoft QuickBASIC versions 4.00, 4.00b,
and 4.50 for MS-DOS; to Microsoft BASIC Compiler versions 6.00 and
6.00b for MS-DOS; and to Microsoft BASIC Professional Development
System (PDS) versions 7.00 and 7.10 for MS-DOS.

The following program demonstrates how to call interrupt &H2F to
detect if SHARE.EXE is loaded. It makes the interrupt call and then
PRINTs what the three separate types of returns can mean. To use this
program in the QB.EXE or QBX.EXE environment, use the /L environment
switch to load the default Quick library, QB.QLB (or QBX.QLB for BASIC
PDS 7.00 or 7.10). To make an executable program from this code, you
must link with the library, QB.LIB (or QBX.LIB for BASIC PDS 7.00 or
7.10).

Program Example
---------------

' Use 'QBX.BI' with BASIC PDS 7.10 or 7.00 instead of 'QB.BI':
REM $INCLUDE: 'QB.BI'

DIM inregs as regtype
DIM outregs as regtype
inregs.ax = &H1000
CALL interrupt(&H2F,inregs,outregs)

' CHECK results.
IF outregs.ax = &HFF THEN
   PRINT "SHARE.EXE installed"
ELSEIF outregs.ax = &H1 THEN
   PRINT "SHARE.EXE not installed, NOT O.K. to install"
ELSE  ' outregs.ax = &H0
   PRINT "SHARE.EXE not installed, O.K. to install"
ENDIF
END

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