From: Jonathan Wakely <jwakely@redhat.com>
To: Martin Sebor <msebor@gmail.com>
Cc: libstdc++ <libstdc++@gcc.gnu.org>, gcc-patches <gcc-patches@gcc.gnu.org>
Subject: Re: [patch] libstdc++/67173 Fix filesystem::canonical for Solaris 10.
Date: Wed, 16 Sep 2015 16:05:00 -0000 [thread overview]
Message-ID: <20150916160221.GZ2631@redhat.com> (raw)
In-Reply-To: <20150916144207.GY2631@redhat.com>
On 16/09/15 15:42 +0100, Jonathan Wakely wrote:
>@@ -22,6 +22,8 @@
> // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
> // <http://www.gnu.org/licenses/>.
>
>+#define _XOPEN_SOURCE 700
>+
> #include <experimental/filesystem>
> #include <functional>
> #include <stack>
Unfortunately this completely breaks NetBSD, because defining
_XOPEN_SOURCE for this one file is inconsistent with how the autconf
test were run, so C99 functions that were implicitly available during
configure tests (because no _POSIX_C_SOURCE, _XOPEN_SOURCE etc. macro
was defined) are no longer available when compiling this translation
unit with _XOPEN_SOURCE defined.
Specifically, <wchar.h> in NetBSD 5.1 does:
#if !defined(_ANSI_SOURCE) && !defined(_POSIX_C_SOURCE) && \
!defined(_XOPEN_SOURCE) && !defined(_NETBSD_SOURCE)
#define _NETBSD_SOURCE 1
#endif
...
#if defined(_ISOC99_SOURCE) || (__STDC_VERSION__ - 0) > 199901L || \
defined(_NETBSD_SOURCE)
int vfwscanf(FILE * __restrict, const wchar_t * __restrict, _BSD_VA_LIST_);
So it's defined during configure and we define _GLIBCXX_HAVE_VFWSCANF
and our <cwchar> does:
#if _GLIBCXX_HAVE_VFWSCANF
using ::vfwscanf;
#endif
but the value of _GLIBCXX_HAVE_VFWSCANF determined during configure is
not valid in src/filesystem/ops.cc after defining _XOPEN_SOURCE.
I don't know how to use _XOPEN_VERSION or _POSIX_VERSION to check for
a suitable realpath without defining one of those feature-test macros,
which then breaks other things.
(This is fixed in NetBSD 7.x which knows about C++11 and so defines
vfwscanf more liberally, but that doesn't help NetBSD 5.1).
Maybe I should just give up on realpath() and use my new
implementation everywhere :-(
next prev parent reply other threads:[~2015-09-16 16:02 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-11 14:23 Jonathan Wakely
2015-09-11 18:05 ` Martin Sebor
2015-09-12 10:39 ` Jonathan Wakely
2015-09-12 19:49 ` Martin Sebor
2015-09-12 22:00 ` Martin Sebor
2015-09-16 14:52 ` Jonathan Wakely
2015-09-16 16:05 ` Jonathan Wakely [this message]
2015-09-16 16:11 ` Jonathan Wakely
2015-09-16 17:38 ` Martin Sebor
2015-09-16 19:02 ` Jonathan Wakely
2015-09-16 22:17 ` Martin Sebor
2015-09-16 22:23 ` Jonathan Wakely
2015-09-16 23:51 ` Martin Sebor
2015-09-17 11:31 ` Jonathan Wakely
2015-09-17 11:33 ` Jonathan Wakely
2015-09-17 14:38 ` Jonathan Wakely
2015-09-17 15:40 ` Martin Sebor
2015-09-23 12:14 ` Jonathan Wakely
2015-09-16 23:42 ` Jonathan Wakely
2015-09-17 15:36 ` Jonathan Wakely
2015-09-17 19:27 ` Andreas Schwab
2015-09-17 22:23 ` Jonathan Wakely
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