From: Martin Str|mberg <ams AT ludd DOT luth DOT se>
Message-Id: <200104151316.PAA07985@mother.ludd.luth.se>
Subject: _creatnew() failing
To: djgpp-workers AT delorie DOT com (DJGPP-WORKERS)
Date: Sun, 15 Apr 2001 15:16:17 +0200 (MEST)
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Reply-To: djgpp-workers AT delorie DOT com

It has been hammered into me that unsupported INT21 functions do not
set the carry flag and only set AL to 0. Well, if that is so
_creatnew() is broken:

int
_creatnew(const char* filename, int attrib, int flags)
{
...
    if (_osmajor > 3)
      r.x.ax = 0x6c00;
    else
    {
      r.h.ah = 0x5b;
      r.x.bx = 0;               /* lose support for fancy flags in DOS
3.x */
      r.x.dx = __tb_offset;
      r.x.si = 0;
    }
  }
  r.x.cx = attrib & 0xffff;
  r.x.ds = __tb_segment;
  __dpmi_int(0x21, &r);
  if(r.x.flags & 1)
  {
    errno = __doserr_to_errno(r.x.ax);
    return -1;
  }
...

FreeDOS claims to be DOZE 5.0 but it does not support INT21,
AX=0x6c00. So this _creatnew() happily thinks is has successfully
opened/created the file in question.

On the other hand it could be argued that a DOZE of version 5.0 must
support INT21, AX=0x6c00...


Right,

						MartinS