2012/8/17 Jacek Caban <[email protected]>
> On 08/17/12 11:42, Rainer Emrich wrote:
> > Am 17.08.2012 11:29, schrieb Kai Tietz:
> > > Hallo Rainer,
> >
> > > well, the issue is that msvcrt's getcwd has as second argument the
> > > pointer-length-argument typed as 'int'. You can check this also by
> > > seaching on msdn for getcwd. For 32-bit it is just a sign-difference of
> > > this argument, which is pretty unlikely to reach (0x7fffffffu +
> > 1u). For
> > > 64-bit is sizeof(size_t) > sizeof(int), which means that we get a
> > > value-truncation and a sign-difference. Not that it is likely that
> > > somebody calls getcwd with pointer-length-argument bigger then 2^31
> > value.
> >
> > > So I would like to get first the opinion of Jacek, and Ozkan about
> > this. It
> > > might be more an issue of the prototype in gcc IMHO.
> >
> > The prototype conforms to the Linux man pages and POSIX.2001
>
Windows isn't POSIX. Nor Linux.
MinGW-w64 is compatible with the Microsoft CRT, which declares getcwd with
a second parameter of type int:
http://msdn.microsoft.com/en-us/library/sf98bd4y%28v=vs.110%29.aspx
>
> Although POSIX version seems better, we have to deal with the fact that
> it's int on Windows. Why does GCC declare it in its headers in the first
> place? It seems like it should use host headers for getcwd declaration.
> This way there would be no conflict.
>
IMO, the GCC header needs an #if _WIN32 for this case. In the worst case,
like this:
#if _WIN32
inline char *getcwd( char *buffer, size_t maxlen ) { return _getcwd(buffer,
(int)maxlen); }
#else
char *getcwd( char *buffer, size_t maxlen );
#endif
The C++ overload mechanism and the cast will take care of all the
differences at call sites of this function.
I do agree with Jacek that GCC should include the platform headers. This
will not fix warnings/errors caused by calling the MS version of getcwd
with a second parameter of type size_t (truncation of a value might cause
an error, especially with -Werror). There's also the extra underscore. Both
problems are alleviated with the above snippet of code, assuming maxlen
stays within a reasonable range.
Ruben
>
> Jacek
>
>
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