DOS ain't dead

recursing subdirectories - redirector (Developers)

posted by usotsuki, 25.10.2025, 18:15

> > > Although closer inspection:
> > > https://www.ctyme.com/intr/rb-2977.htm#Table1626
> > >
> > > suggests that this is a fixed size that won't be expanded with new DOS
> > > versions.
> > >
> > > And that size is decimal 43 bytes.
> >
> > That tracks, yes.
>
> Did Microsoft document this somewhere?
>
> ie before calling FindFirst, you should SET the DTA to point to
> a 43-byte buffer?
>
> If not, how are you supposed to know something like this?
> ie that Microsoft guarantees that you only need 43 bytes
> for eternity. And that it doesn't need to be aligned on any
> particular boundary (2/4/8/16/32 bytes).
>
> Thanks. Paul.

Programmers' manuals from Microsoft for multiple versions of MS-DOS (I checked 2.0, 3.2 and 4.0) describe a 43-byte struct. The 3.2 and 4.0 manuals have example code that reserves exactly 43 bytes for a findfirst buffer.

Complete thread:

• recursing subdirectories - kerravon, 20.10.2025, 08:15 (Developers)
  • recursing subdirectories - ecm, 20.10.2025, 08:54
    • recursing subdirectories - kerravon, 20.10.2025, 18:02
      • recursing subdirectories - redirector - ecm, 20.10.2025, 20:30
        • recursing subdirectories - redirector - ecm, 20.10.2025, 20:33
        • recursing subdirectories - redirector - kerravon, 25.10.2025, 16:56
          • recursing subdirectories - redirector - usotsuki, 25.10.2025, 18:15
            • recursing subdirectories - redirector - kerravon, 26.10.2025, 03:22
              • recursing subdirectories - redirector - Rugxulo, 26.10.2025, 03:34