Click above to get retro games delivered to your door ever month!

 intdosx()               Set Seg Regs and Invoke DOS Function, Long Form

 #include   <dos.h>

 int          intdosx(inregs,outregs,segregs);
 union REGS    *inregs;                  Register values going into call
 union REGS    *outregs;                 Register values on return
 struct SREGS  *segregs;                 ES and DS values going into call

    intdosx() invokes a DOS system call (Interrupt 0x21) after setting
    the registers to the values in 'inregs' and setting the DS and ES
    registers to the values in 'segregs'. 'outregs' is set to the value
    of the registers after the system call.  The 'cflag' field of
    'outregs' is set to the status of the system carry flag; a non-zero
    value indicates a DOS error. 'inregs.h.ah' is the DOS function
    number.

       Returns:     The value of the AX register after the system call.
                    If the 'cflag' field in 'outregs' is non-zero, an
                    error has occurred and '_doserrno' (defined in
                    <errno.h>) is set to the error code.

         Notes:     The values for segment registers can be obtained with
                    the segread() function or the FP_SEG() macro.

                    If the DS and ES registers don't need to be set,
                    intdos() can be used.

                    DOS functions that use only the DX and AL registers
                    and that don't return error information in the carry
                    flag can be invoked via the bdos() or the bdosptr()
                    function. Note that neither allow the setting of the
                    segment register ES.

   Portability:     MS-DOS only.

   -------------------------------- Example ---------------------------------

    The following statements output 'string' to the standard output.

           #include <dos.h>      /* intdosx(), macros FP_SEG() and FP_OFF(),
                                    union REGS and struct SREGS */

           union REGS inregs, outregs;
           struct SREGS segregs;
           char far *string =
                         "this string is not in the default data segment$";

           main()
           {
               inregs.h.ah = 0x9;         /* output string function number */
               inregs.x.dx = FP_OFF(string);/*DS:DX is address of 'string*/
               segregs.ds = FP_SEG(string);
               intdosx(&inregs, &outregs, &segregs);
           }