Re: [Caml-list] Re: portable truncate

[Florent Monnier <monnier.florent@gmail.com>]

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.

>> - 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


>> Don't you think that "win32unix/" should remain as is for the MS
>> compiler, and that mingw variant should just switch to
>> "otherlibs/unix/" ?
>
> No. Mingw is not posix. Just think about fork(): it cannot exist on
> Windows currently without resorting to the big layer that Cygwin
> provides (along with its performance hit).
>
> Btw, you can have a look at this entry in the Cygwin FAQ to better
> understand what "cygwin" means:
>   http://cygwin.com/faq.html#faq.api.fork

Interesting, thanks a lot.

> You can also take a look at the C files in otherlibs/win32unix: there's
> quite a lot of work that is done to provide a matching API.

Thanks, it made me discovered about the Handle_val() convertion that
only exists in win32unix.


> You can use the eval editions that are available on Microsoft's website.
> They're time-limited (one month for some) and after that they will
> shutdown after 1 hour but that's not an issue for testing, especially
> for VMs. There are also ways to extend the original one-month period
> that are documented on MSDN.
>
> (you can also reinstall: qemu's cache=unsafe disk parameter makes
> installation insanely fast; yypkg's mingw-builds should also make
> installation of a build environment much faster)

Thanks a lot Adrien,
your answers are very interesting!

-- 
Regards