A Tuesday 12 February 2008 23:23:09, Danny Backx wrote:
> On Tue, 2008-02-12 at 12:03 +0900, Lance Fetters wrote:
> > Unfortunately I haven't been able to switch to mingw32ce so far for
> > various reasons, including that mingw32ce seems to be missing some win32
> > functionality, particularly _get_osfhandle() (declared but not defined),
> > which is being used for loadable module support. Is there an alternative
> > function that should be used?.
>
> According to MSDN (see e.g. http://support.microsoft.com/kb/99456) the
> _get_osfhandle is not supported in Win32. Also searching for the
> combination of _get_osfhandle and ce fails, which indicates that the
> call is not supported on Windows CE either.
>
Remember that a file descriptor in Windows CE is really a handle. While
on desktop Windows, you need this, to get at the win32 file handle:
FILE *f = fopen (...);
HANDLE h = (HANDLE)_get_osfhandle (_fileno (f));
On Windows CE, you can do this directly:
FILE *f = fopen (...);
HANDLE h = (HANDLE) _fileno (f);
What you can do for WinCE, is something like:
#define _get_os_fhandle (FILDES) ((long) (FILDES))
(don't we have this in mingw32ce headers?)
And there you go, instant portability:
FILE *f = fopen (...);
HANDLE h = (HANDLE)_get_osfhandle (_fileno (f));
The file descriptor == HANDLE is also the reason why you should be
careful with code like:
if (open (...) < 0)
{
/* error */
}
A handle represented as an int can be negative, and that is not an error.
You should change that to:
if (open (...) == -1)
{
/* error */
}
That will work everywhere. Posix, Wince and Windows CE.
Also, for the same reasons, you should not hardcode 0, 1 and 2 as stdin,
stdout and stderr file descriptors. Use the STDIN_FILENO, STDOUT_FILENO,
and STDERR_FILENO macros.
We should put this stuff somewhere in the mingw32ce docs.
--
Pedro Alves
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