PRODUCT  :  Borland C++                            NUMBER  :  713
  VERSION  :  2.0
       OS  :  DOS
     DATE  :  October 26, 1993                         PAGE  :  1/3

    TITLE  : Switching a Device Driver Between Cooked and Raw Mode




  /**************************************************************************
      FUNCTION:  setdevmode

          PURPOSE:
                  This function will swap a device driver
                  associated with the given stream into either a
                  raw (binary) or a cooked (ASCII) mode. This is
                  useful for outputting to the screen or printer in
                  a binary mode.  Note that once this bit is set
                  all output to the device is received from the
                  device driver in the mode indicated by bit 5.
                  This is true even if you do not use a binary read
                  or write command.

          METHOD:
                  This function will call, via the ioctl()
                  function,  int 21h / function 44h / subfunction 0
                  to get the current device status word.  The high
                  order byte of the word is then cleared and then
                  bit 5 is set to the selected mode. The ioctl() is
                  then again called this time using subfunction 1
                  to set a new status.

          PARAMETERS:
                  This function takes two arguments, both are type
                  integer.  The first is the number of the handle
                  associated with the targeted device driver.  The
                  second is the mode the device driver is to be put
                  into:

                          1 = raw (binary) mode
                          2 = cooked (ASCII) mode

                  All other values for parameters are invalid and
                  will generate an error.

          RETURN VALUE:
                  This function will return a 0 on error, 1 if
                  the new mode is raw and 2 if the new mode is
                  cooked.
















  PRODUCT  :  Borland C++                            NUMBER  :  713
  VERSION  :  2.0
       OS  :  DOS
     DATE  :  October 26, 1993                         PAGE  :  2/3

    TITLE  :  Switching a Device Driver Between Cooked and Raw Mode




          IMPLEMENTATION:
                  This function can be implemented by including the
                  prototype:  " int setdevmode( int, int); " within
                  file scope of your calling program.  Within file
                  scope implies external to all functions. You
                  would then need to compile this file and link it
                  into the executable. Once this is done you can
                  simply make function calls to setdevmode() like
                  any other function.

  ***********************************************************************/

  #include <io.h>

  int setdevmode(int handle, int mode)
  {
     int ret,                   /* Function return value         */
         word,                  /* Device driver status          */
         mask =  0x0020,        /* Mask to set bit 5             */
         mask2 = 0x00ff,        /* Mask to clear high order bits */
         mask3 = 0x00df;        /* Mask to clear bit 5           */

    if( mode < 1 || mode >2 )   /* Check for a valid mode        */
            return (0);

    word = ioctl( handle, 0, 0, 0 ); /* Get current driver status*/
    if( word == -1 )            /* Check for an error            */
       return (0);

    word &= mask2;              /* Clear high order bits         */
    if( word & mask )           /* Check if bit 5 is set (raw)   */
    {
       if( mode == 2 )          /* Check if ASCII is requested   */
         word &= mask3;         /* Clear bit 5 setting cooked    */
    }
    else
       if( mode == 1 )          /* Check if binary is requested  */
         word |= mask;          /* Set bit 5 setting raw         */

    ret = ioctl( handle, 1, word, 0); /* Change the device driver
                                         status */















  PRODUCT  :  Borland C++                            NUMBER  :  713
  VERSION  :  2.0
       OS  :  DOS
     DATE  :  October 26, 1993                         PAGE  :  3/3

    TITLE  :  Switching a Device Driver Between Cooked and Raw Mode




    if( ret == -1 )             /* Check for an error            */
       return (0);
    else
       return (mode);           /* Return new device driver mode */
  }

  DISCLAIMER: You have the right to use this technical information
  subject to the terms of the No-Nonsense License Statement that
  you received with the Borland product to which this information
  pertains.