re PR libstdc++/56193 (ios_base should replace operator void* with explicit…

re PR libstdc++/56193 (ios_base should replace operator void* with explicit operator bool in C++11 onwards.)

	PR libstdc++/56193
	* config/abi/pre/gnu.ver: Add new exports.
	* include/bits/basic_ios.h (basic_ios::operator bool): Define.
	* src/c++98/ios_locale.cc (basic_ios::operator void*): Instantiate.

From-SVN: r215571

libstdc++-v3/ChangeLog

@@ -3,6 +3,11 @@
 	* config/abi/pre/gnu.ver: Make GLIBCXX_3.4 patterns stricter so the
 	new GLIBCXX_3.4.21 symbols don't match them.
 
+	PR libstdc++/56193
+	* config/abi/pre/gnu.ver: Add new exports.
+	* include/bits/basic_ios.h (basic_ios::operator bool): Define.
+	* src/c++98/ios_locale.cc (basic_ios::operator void*): Instantiate.
+
 2014-09-24  François Dumont  <fdumont@gcc.gnu.org>
 
 	PR libstdc++/29988

libstdc++-v3/config/abi/pre/gnu.ver

@@ -1470,6 +1470,9 @@ GLIBCXX_3.4.21 {
     _ZNSoC[12]ERSd;
     _ZNSt13basic_ostreamIwSt11char_traitsIwEEC[12]ERSt14basic_iostreamIwS1_E;
 
+    # std::basic_ios::operator bool() const
+    _ZNKSt9basic_iosI[cw]St11char_traitsI[cw]EEcvbEv;
+
 } GLIBCXX_3.4.20;
 
 

libstdc++-v3/include/bits/basic_ios.h

@@ -113,8 +113,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *  This allows you to write constructs such as
        *  <code>if (!a_stream) ...</code> and <code>while (a_stream) ...</code>
       */
+#if __cplusplus >= 201103L
+      explicit operator bool() const
+      { return !this->fail(); }
+#else
       operator void*() const
       { return this->fail() ? 0 : const_cast<basic_ios*>(this); }
+#endif
 
       bool
       operator!() const

libstdc++-v3/src/c++98/ios_locale.cc

@@ -54,5 +54,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     return __old;
   }
 
+  // Explicit instantiations for basic_ios are done in src/c++11/ios.cc
+  // and so do not include this member, which is only defined for C++98.
+  template basic_ios<char>::operator void*() const;
+#ifdef _GLIBCXX_USE_WCHAR_T
+  template basic_ios<wchar_t>::operator void*() const;
+#endif
+
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace