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Re: [PATCH 64bit] Export <io.h> symbols with underscore


On Feb 22 10:27, Christopher Faylor wrote:
> On Fri, Feb 22, 2013 at 03:44:48PM +0100, Corinna Vinschen wrote:
> >On Feb 22 09:32, Christopher Faylor wrote:
> >> On Fri, Feb 22, 2013 at 11:02:55AM +0100, Corinna Vinschen wrote:
> >> >On Feb 22 10:51, Corinna Vinschen wrote:
> >> >> On Feb 22 03:40, Yaakov wrote:
> >> >> > On Fri, 22 Feb 2013 09:49:51 +0100, Corinna Vinschen wrote:
> >> >> > > > access should go, no doubt about it.
> >> >> > > > 
> >> >> > > > For get_osfhandle and setmode I would prefer maintaining backward
> >> >> > > > compatibility with existing applications.  Both variations, with and
> >> >> > > > without underscore are definitely in use.
> >> >> > > > 
> >> >> > > > What about exporting the underscored variants only, but define the
> >> >> > > > non-underscored ones:
> >> >> > > > 
> >> >> > > >   extern long _get_osfhandle(int);
> >> >> > > >   #define get_osfhandle(i) _get_osfhandle(i)
> >> >> > > > 
> >> >> > > >   extern int _setmode (int __fd, int __mode);
> >> >> > > >   #define setmode(f,m) _setmode((f),(m))
> >> >> > > 
> >> >> > > Just to be clear:  On 32 bit we should keep the exported symbols, too.
> >> >> > > On 64 bit we can drop the non-underscored ones (which just requires
> >> >> > > to rebuild gawk for me) and only keep the defines for backward
> >> >> > > compatibility.
> >> >> > 
> >> >> > Like this?
> >> >> 
> >> >> Almost.  The _setmode needs a tweak, too.  I also think it makes
> >> >> sense to rename the functions inside of syscalls.cc:
> >> >> [...]
> >> >
> >> >I applied this patch to the 64 bit branch for now.
> >> 
> >> I was actually expecting that we'd break the compilation of existing
> >> applications which incorrectly referenced get_osfhandle and setmode (I
> >> have a couple of those).  It's a simple fix if someone recompiles and
> >> it wouldn't be the first time that you'd have to make a source code
> >> change when upreving to a new "OS".  For 32-bit we would need to keep
> >> both in cygwin.din though, of course.
> >
> >I'm trying to keep up with backward compatibility on the source level
> >as far as it makes sense (for a given value of "sense").
> 
> Yeah, but I worry about carrying cruft like this around forever.  I know
> it's a mile pain for the person who copmiles programs but it shouldn't
> be that big a deal to add an underscore.

Alternatively, we We keep exporting the unloved symbols and add an
__attribute__ ((deprecated)) in the header, as we did for
cygwin_conv_to_win32_path and friends.  

> >> But, if you're going to use defines, why not just simplify them as:
> >> 
> >> #define get_osfhandle _get_osfhandle
> >> #define setmode _setmode
> >
> >I can do that, but I thought error messages would be more meaningful
> >when using macros with arguments.  Dunno, I was just trying to do
> >it right.  Shall I still simplify them?
> 
> I don't know.  If you use your method and say, for example setmode(x)
> you'll get an error about a macro lacking arguments.  If you said
> setmode ((char *) foo) you'd get an error about the '_setmode' function.
> If you defined the macro without arguments you'd get a compiler error
> referencing '_setmode' in both cases.  I guess I'd want this to be
> consistent but I don't really care that much.

Me neither.  I can define them just by name, but that depends on the
above decision.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat


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