Re: [Caml-list] Re: portable truncate

[Adrien Nader <adrien@notk.org>]

On Sat, Jul 27, 2013, Florent Monnier wrote:
> 2013/07/27, Adrien Nader wrote:
> [...]
> > It's a very minimal layer. Microsoft CRT cannot be used for things like
> > printing properly long doubles or similar things. Its math
> > implementation is also lacking some C99 support (plus it's not that
> > fast). That's where the mingw CRT will provide you more things. For
> > others, it's the Microsoft one.
> 
> mingw's additional lib has to be used if we're using thread for
> example if I have understood correctly.

What makes you think so?

A quick look seems to indicate the opposite. There is no specific thread
support provided by mingw*.
There are pthreads-win32 and winpthreads but I don't see the build
system use them on Windows; I see calls to CreateThead() (typical win32
stuff) however for instance.

> >> - truncate()  DOES work on my computer
> >> - ftruncate() / _chsize()  DOESN'T
> >
> > That's surprising and you should really try to see which error you get
> > throw errno. You can also try a tool like FileMonitor (or whatever it's
> > called nowadays) to see how it fails.
> 
> I get EBADF
> 
> http://msdn.microsoft.com/en-us/library/dk925tyb%28v=VS.80%29.aspx
> 
> EBADF is if the specified file is read-only or the descriptor is invalid
> 
> the file has write access for everyone.
> And the file descriptor is converted the same way than everywhere else.
> 
> Then I noticed that I copied the stub from otherlibs/unix/ not from
> otherlibs/win32unix/
> so the file descr is converted by Int_val() instead of Handle_val().
> 
> But now I still get : EBADF

And you've opened the file as read-write too?
If so, you should maybe try Process Monitor to make sure everything was
done as expected:
  http://technet.microsoft.com/en-us/sysinternals/bb896645.aspx

-- 
Adrien Nader