Encapsulating the DOS IOCTL Interface

Listing 2 iobase.cpp — IOCTL base class implementation

#include "iobase.h"

IoctlBase::IoctlBase()    {
   _iregs.h.ah = 0x30;  //Get MS-DOS version

   intdosx( &_iregs, &_oregs, &_sregs );
   _dos.ver.major = _oregs.h.al;
   _dos.ver.minor = _oregs.h.ah;
   _dos_error = 0;
}
void IoctlBase::int21_44h( ioctl_cmd code )   {
  /* DOS IOCTL (21h/44h) service call ...... */
   _iregs.h.ah = 0x44;   //function number
   _iregs.h.al = code;   //subfunction
   intdosx( &_iregs, &_oregs, &_oregs );
   _dos_error = _oregs.x.cflag ? _oregs.x.ax : 0;
   if(_dos_error )
      IoctlError(_dos_error );
}

// End of File