Pascal Example in Programmer's Guide Won't Compile (68881)

The information in this article applies to:
    Microsoft Mouse driver for MS-DOS 9.0
    Microsoft Mouse driver for MS-DOS 6.x
    Microsoft Mouse driver for MS-DOS 7.x
    Microsoft Mouse driver for MS-DOS 8.x

This article was previously published under Q68881


The "Making Calls from Borland Turbo Pascal Programs" sample in Appendix E of the "Microsoft Mouse Programmer's Reference" does not compile with Turbo Pascal versions 5.0 and 6.0.


The CpuReg data structure needs to be defined as "Registers" variables. The semicolons need to be removed from the END lines that immediately precede ELSE. Finally, finding the segment and offset of the pointer of the address of the user array or subroutine (functions 9,12,20,22,23,and 24) needs to be done outside of this procedure. Passing the first element of the array or the start point of the subroutine into the procedure, then calling the "ofs" and "seg" functions in the procedure doesn't seem to work. This is due to how the variables get dereferenced when passed into a procedure.

The following example compiles in both Turbo Pascal version 6.0 and Quick Pascal version 1.00:
Procedure Mouse (Var m1, m2, m3, m4, m5 : integer );

   CpuReg: Registers;

begin {mouse}

   if m1 >= 0 then
     CpuReg.AX := m1;        { Load Parameters       }
     CpuReg.BX := m2;        { into appropriate      }
     CpuReg.CX := m3;        { registers             }

     if (m1 = 9) or (m1 = 12) or (m1 = 20)
        or (m1 = 22) or (m1 = 23) or (m1 = 24) then
          CpuReg.DX  :=  m4;    {m4 = offset,         }
          CpuReg.ES  :=  m5;    { and m5 = segment    }
        end                       { of the user array }
                         { or subroutine     }

      if  m1 = 16  then
         CpuReg.CX  := m2;           {Left  x coordinate }
         CpuReg.DX  := m3;           {Upper y coordinate }
         CpuReg.SI  := m4;           {Right x coordinate }
         CpuReg.DI  := m5;           {Lower y coordinate }
         CpuReg.DX  := m4;

     Intr($33, CpuReg);              {Call mouse driver  }
                            { at Interrupt 33H  }

     m1 := CpuReg.AX;                {Return values back }
     m2 := CpuReg.BX;                { to parameters     }
     m3 := CpuReg.CX;
     m4 := CpuReg.DX;

     if (m1 = 20) then               {special returns    }
        m2 := CpuReg.ES              { from subroutines  }
end; {mouse}
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Modification Type: Major Last Reviewed: 9/24/2003
Keywords: KB68881