libstdc++/77795 Only declare ::gets for C++98 and C++11

	PR libstdc++/77795
	* acinclude.m4 (GLIBCXX_CHECK_STDIO_PROTO): Use -std=gnu++11 to check
	for gets.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* include/c_global/cstdio [!_GLIBCXX_HAVE_GETS] (gets): Only declare
	for C++98 and C++11.
	* include/c_std/cstdio [!_GLIBCXX_HAVE_GETS] (gets): Likewise.
	* testsuite/27_io/headers/cstdio/functions_neg.cc: New test.

From-SVN: r240672

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index f73e62e4789d5f7bbeeea25bb227aea6b7f60f1b..be41539547da0bfba94f22600c77a8b97c4501ad 100644 (file)
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,15 @@
 2016-09-30  Jonathan Wakely  <jwakely@redhat.com>
 
+       PR libstdc++/77795
+       * acinclude.m4 (GLIBCXX_CHECK_STDIO_PROTO): Use -std=gnu++11 to check
+       for gets.
+       * config.h.in: Regenerate.
+       * configure: Regenerate.
+       * include/c_global/cstdio [!_GLIBCXX_HAVE_GETS] (gets): Only declare
+       for C++98 and C++11.
+       * include/c_std/cstdio [!_GLIBCXX_HAVE_GETS] (gets): Likewise.
+       * testsuite/27_io/headers/cstdio/functions_neg.cc: New test.
+
        * doc/xml/manual/intro.xml: Document LWG 2192 changes.
        * doc/html/*: Regenerate.
        * include/Makefile.am: Add bits/std_abs.h.

diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index ffead7dfd4c3917180d39b24341654d35fdb088e..d0ee45fb49b6a7145bd84a2fee08578e1ac71177 100644 (file)
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -2153,6 +2153,10 @@ AC_DEFUN([GLIBCXX_CHECK_STDIO_PROTO], [
 
   AC_LANG_SAVE
   AC_LANG_CPLUSPLUS
+  # Use C++11 because a conforming <stdio.h> won't define gets for C++14,
+  # and we don't need a declaration for C++14 anyway.
+  ac_save_CXXFLAGS="$CXXFLAGS"
+  CXXFLAGS="$CXXFLAGS -std=gnu++11"
 
   AC_MSG_CHECKING([for gets declaration])
   AC_CACHE_VAL(glibcxx_cv_gets, [
@@ -2168,10 +2172,11 @@ AC_DEFUN([GLIBCXX_CHECK_STDIO_PROTO], [
       )])
 
   if test $glibcxx_cv_gets = yes; then
-    AC_DEFINE(HAVE_GETS, 1, [Define if gets is available in <stdio.h>.])
+    AC_DEFINE(HAVE_GETS, 1, [Define if gets is available in <stdio.h> before C++14.])
   fi
   AC_MSG_RESULT($glibcxx_cv_gets)
 
+  CXXFLAGS="$ac_save_CXXFLAGS"
   AC_LANG_RESTORE
 ])
 

diff --git a/libstdc++-v3/config.h.in b/libstdc++-v3/config.h.in
index 2ab6e0d6a49a14c4900a495e89aeb5241b267cf9..63996709ad49a28d2e4d26d967e84ce51e4f33ea 100644 (file)
--- a/libstdc++-v3/config.h.in
+++ b/libstdc++-v3/config.h.in
@@ -183,7 +183,7 @@
 /* Define if _Unwind_GetIPInfo is available. */
 #undef HAVE_GETIPINFO
 
-/* Define if gets is available in <stdio.h>. */
+/* Define if gets is available in <stdio.h> before C++14. */
 #undef HAVE_GETS
 
 /* Define to 1 if you have the `hypot' function. */

diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index f7b424b9e63554dc238293a1aaabe8d78f49b16d..09b73b8589123b3404c7574347f6e02f63fc333f 100755 (executable)
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -18176,6 +18176,10 @@ ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
 ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
 ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
+  # Use C++11 because a conforming <stdio.h> won't define gets for C++14,
+  # and we don't need a declaration for C++14 anyway.
+  ac_save_CXXFLAGS="$CXXFLAGS"
+  CXXFLAGS="$CXXFLAGS -std=gnu++11"
 
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for gets declaration" >&5
 $as_echo_n "checking for gets declaration... " >&6; }
@@ -18210,6 +18214,7 @@ $as_echo "#define HAVE_GETS 1" >>confdefs.h
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: $glibcxx_cv_gets" >&5
 $as_echo "$glibcxx_cv_gets" >&6; }
 
+  CXXFLAGS="$ac_save_CXXFLAGS"
   ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'

diff --git a/libstdc++-v3/include/c_global/cstdio b/libstdc++-v3/include/c_global/cstdio
index 920d109bcb8a1e4208e3d59a0b4373ff906c6867..86d524f96a626d231dac925eb3890060f53694de 100644 (file)
--- a/libstdc++-v3/include/c_global/cstdio
+++ b/libstdc++-v3/include/c_global/cstdio
@@ -44,7 +44,7 @@
 #ifndef _GLIBCXX_CSTDIO
 #define _GLIBCXX_CSTDIO 1
 
-#ifndef _GLIBCXX_HAVE_GETS
+#if __cplusplus <= 201103L && !defined(_GLIBCXX_HAVE_GETS)
 extern "C" char* gets (char* __s) __attribute__((__deprecated__));
 #endif
 

diff --git a/libstdc++-v3/include/c_std/cstdio b/libstdc++-v3/include/c_std/cstdio
index a4119ba6c64e4dd588d392f85ebe775b90be78f9..549004c0a165ee615b16ccaab8e3e454b40d5909 100644 (file)
--- a/libstdc++-v3/include/c_std/cstdio
+++ b/libstdc++-v3/include/c_std/cstdio
@@ -44,7 +44,7 @@
 #include <bits/c++config.h>
 #include <stdio.h>
 
-#ifndef _GLIBCXX_HAVE_GETS
+#if __cplusplus <= 201103L && !defined(_GLIBCXX_HAVE_GETS)
 extern "C" char* gets (char* __s) __attribute__((__deprecated__));
 #endif
 

diff --git a/libstdc++-v3/testsuite/27_io/headers/cstdio/functions_neg.cc b/libstdc++-v3/testsuite/27_io/headers/cstdio/functions_neg.cc
new file mode 100644 (file)
index 0000000..f9e5f86
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/headers/cstdio/functions_neg.cc
@@ -0,0 +1,25 @@
+// { dg-do compile  { target c++14 } }
+
+// Copyright (C) 2007-2016 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include <cstdio>
+
+namespace gnu
+{
+  using std::gets; // { dg-error "has not been declared" }
+}