Re: fdopen on MSVC

[Eric Blake]

On 09/26/2011 04:17 PM, Bruno Haible wrote:
> Paolo Bonzini asked:
> > >         * modules/fclose-tests (Depends-on): Add fdopen.
> > >         * modules/fflush-tests (Depends-on): Likewise.
> > >         * modules/fgetc-tests (Depends-on): Likewise.
> > >         * modules/fputc-tests (Depends-on): Likewise.
> > >         * modules/fread-tests (Depends-on): Likewise.
> > >         * modules/freopen-tests (Depends-on): Likewise.
> > >         * modules/fseeko-tests (Depends-on): Likewise.
> > >         * modules/ftello-tests (Depends-on): Likewise.
> > >         * modules/fwrite-tests  (Depends-on): Likewise.
> >
> > Why?
>
> These tests (test-fgetc.c etc.) call fdopen (-1, "r"), which is supposed
> to return NULL / EBADF. But -- see doc/posix-functions/fdopen.texi --
> this call crashes on MSVC 9, and the gnulib 'fdopen' module provides the
> workaround (through an invalid parameter handler that prevents the crash).

If fdopen(-1,"r") returns anything besides NULL in the first place, then 
that is a bug in fdopen().  It looks like you are doing some bogus 
testing in these various files:

/* Test that fclose() sets errno if the stream was constructed with
     an invalid file descriptor.  */
  {
    FILE *fp = fdopen (-1, "r");
    if (fp != NULL)
      {
        errno = 0;
        ASSERT (fclose (fp) == EOF);
        ASSERT (errno == EBADF);
      }
  }

since fp should be NULL at this point, and thus a compliant system won't 
be testing fclose() behavior in the first place.

--
Eric Blake   address@hidden    +1-801-349-2682
Libvirt virtualization library http://libvirt.org