Date: Mon, 14 Nov 2011 14:19:14 -0500 From: David Schultz <das@freebsd.org> To: David Chisnall <theraven@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, Stefan Farfeleder <stefanf@freebsd.org>, Dimitry Andric <dim@freebsd.org>, src-committers@freebsd.org Subject: Re: svn commit: r227487 - head/include Message-ID: <20111114191914.GA58676@zim.MIT.EDU> In-Reply-To: <3B8C1412-E18D-47E3-A09D-4847DD078963@FreeBSD.org> References: <201111131618.pADGIm2n099696@svn.freebsd.org> <20111114082129.GA1596@mole.fafoe.narf.at> <4EC0E6C2.4010509@FreeBSD.org> <20111114180235.GA58284@zim.MIT.EDU> <3B8C1412-E18D-47E3-A09D-4847DD078963@FreeBSD.org>
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On Mon, Nov 14, 2011, David Chisnall wrote: > On 14 Nov 2011, at 18:02, David Schultz wrote: > > > On Mon, Nov 14, 2011, Dimitry Andric wrote: > >> On 2011-11-14 09:21, Stefan Farfeleder wrote: > >>> On Sun, Nov 13, 2011 at 04:18:48PM +0000, David Chisnall wrote: > >>>> Author: theraven > >>>> Date: Sun Nov 13 16:18:48 2011 > >>>> New Revision: 227487 > >>>> URL: http://svn.freebsd.org/changeset/base/227487 > >>>> > >>>> Log: > >>>> The spec says that FILE must be defined in wchar.h, but it wasn't. It > >>>> is now. Also hide some macros in C++ mode that will break C++ > >>>> namespaced calls. > >>>> > >>>> Approved by: dim (mentor) > >>> > >>> I think this change is wrong. Whic spec are you referring to? C99 > >>> defines FILE only in 7.19.1#2 (stdio.h). In other headers FILE is used > >>> as parameter type for functions but that does not mean it is exported to > >>> user space. > >> > >> http://pubs.opengroup.org/onlinepubs/007908799/xsh/wchar.h.html > > > > It's a niggling detail, but that's an extension to the C standard, > > so properly speaking, it belongs in an > > #if __POSIX_VISIBLE >= 200809 || XSI_VISIBLE > > (or something like that). The formals were struct __sFILE * > > instead of FILE * for that reason -- see r103177. > > > > P.S. You're looking at a very old version of POSIX. Check out: > > http://pubs.opengroup.org/onlinepubs/9699919799/ > > The C99 and C1x specifications both seem to require stdio.h to be included before wchar.h. I think this therefore places including wchar.h and not stdio.h in the category of undefined (or, at least, not defined) behaviour, so we are free to do anything in this case. I would say that accepting the code and working as the programmer expected is the least harmful thing to do here. This is what Darwin libc does (actually, it #includes stdio.h in wchar.h). The C99 standard has plenty of examples of programs including <wchar.h> but not <stdio.h>. The latter is only required to call the functions that take a FILE * parameter. It's mostly an academic point because no sane programmer would ever create a new type named FILE, but FreeBSD actually did right by C99 before you reverted r103177.
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