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bdosx

Usage

   #include <dos.h>
   int bdosx(int func, char *ptr);

Description

   Calls a DOS function (int 21h) where func is the function number and the
   ptr argument is loaded into the DS:DX register pair. The argument ptr is

   a standard C near or far pointer depending on the memory model. Do not
   specifically use a declared near or far pointer unless it matches the
   default pointer type for the memory model in use. Use intdosx for system
   calls that require registers to be set up.

   Under the X and P memory models bdos() and bdosx() carry out some
   filtering of parameters sent to the real mode interrupt. This filtering
   allows data stored in extended memory to be passed to the DOS function so
   that, for instance, much larger buffers than normal can be used with the
   DOS disk functions. Where pointers are passed to bdosx(), they are
   assumed to contain protected mode addresses. The filtering routine used
   for these functions assumes that all far pointers passed in registers to
   DOS have a segment address of DGROUP. If you use bdosx() and specify a
   selector other that DGROUP the results will be unpredictable.

   Some of the available DOS functions are not supported or only partially
   supported in the X and P memory models, refer to the entry for int86()
   for more information.

Return Value


   Returns the value in AX after the system call.

See Also

   DOS package, bdos, intdos, intdosx, int86, int86x kage,
                bdos, intdos, intdosx, int86, int86x