2017-07-25  Jonathan Wakely  <jwakely@redhat.com>

	PR libstdc++/53984

	* include/bits/basic_ios.h (basic_ios::_M_setstate): Adjust comment.

	* include/bits/istream.tcc (basic_istream::sentry): Handle exceptions

	during construction.

	* include/std/istream: Adjust comments for formatted input functions

	and unformatted input functions.

	* testsuite/27_io/basic_fstream/53984.cc: New.

	* testsuite/27_io/basic_istream/sentry/char/53984.cc: New.

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

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

@@ -157,8 +157,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION

       setstate(iostate __state)

       { this->clear(this->rdstate() | __state); }

-      // Flip the internal state on for the proper state bits, then re

-      // throws the propagated exception if bit also set in

+      // Flip the internal state on for the proper state bits, then

+      // rethrows the propagated exception if bit also set in

       // exceptions().

       void

       _M_setstate(iostate __state)

--- libstdc++-v3/include/bits/istream.tcc

+++ libstdc++-v3/include/bits/istream.tcc

@@ -48,28 +48,36 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION

     {

       ios_base::iostate __err = ios_base::goodbit;

       if (__in.good())

-	{

-	  if (__in.tie())

-	    __in.tie()->flush();

-	  if (!__noskip && bool(__in.flags() & ios_base::skipws))

-	    {

-	      const __int_type __eof = traits_type::eof();

-	      __streambuf_type* __sb = __in.rdbuf();

-	      __int_type __c = __sb->sgetc();

-

-	      const __ctype_type& __ct = __check_facet(__in._M_ctype);

-	      while (!traits_type::eq_int_type(__c, __eof)

-		     && __ct.is(ctype_base::space, 

-				traits_type::to_char_type(__c)))

-		__c = __sb->snextc();

+	__try

+	  {

+	    if (__in.tie())

+	      __in.tie()->flush();

+	    if (!__noskip && bool(__in.flags() & ios_base::skipws))

+	      {

+		const __int_type __eof = traits_type::eof();

+		__streambuf_type* __sb = __in.rdbuf();

+		__int_type __c = __sb->sgetc();

+

+		const __ctype_type& __ct = __check_facet(__in._M_ctype);

+		while (!traits_type::eq_int_type(__c, __eof)

+		       && __ct.is(ctype_base::space,

+				  traits_type::to_char_type(__c)))

+		  __c = __sb->snextc();

-	      // _GLIBCXX_RESOLVE_LIB_DEFECTS

-	      // 195. Should basic_istream::sentry's constructor ever

-	      // set eofbit?

-	      if (traits_type::eq_int_type(__c, __eof))

-		__err |= ios_base::eofbit;

-	    }

-	}

+		// _GLIBCXX_RESOLVE_LIB_DEFECTS

+		// 195. Should basic_istream::sentry's constructor ever

+		// set eofbit?

+		if (traits_type::eq_int_type(__c, __eof))

+		  __err |= ios_base::eofbit;

+	      }

+	  }

+	__catch(__cxxabiv1::__forced_unwind&)

+	  {

+	    __in._M_setstate(ios_base::badbit);

+	    __throw_exception_again;

+	  }

+	__catch(...)

+	  { __in._M_setstate(ios_base::badbit); }

       if (__in.good() && __err == ios_base::goodbit)

 	_M_ok = true;

--- libstdc++-v3/include/std/istream

+++ libstdc++-v3/include/std/istream

@@ -150,9 +150,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION

        *  whatever data is appropriate for the type of the argument.

        *

        *  If an exception is thrown during extraction, ios_base::badbit

-       *  will be turned on in the stream's error state without causing an

-       *  ios_base::failure to be thrown.  The original exception will then

-       *  be rethrown.

+       *  will be turned on in the stream's error state (without causing an

+       *  ios_base::failure to be thrown) and the original exception will

+       *  be rethrown if badbit is set in the exceptions mask.

       */

       //@{

@@ -286,9 +286,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION

        *  by gcount().

        *

        *  If an exception is thrown during extraction, ios_base::badbit

-       *  will be turned on in the stream's error state without causing an

-       *  ios_base::failure to be thrown.  The original exception will then

-       *  be rethrown.

+       *  will be turned on in the stream's error state (without causing an

+       *  ios_base::failure to be thrown) and the original exception will

+       *  be rethrown if badbit is set in the exceptions mask.

       */

       /**

--- /dev/null

+++ libstdc++-v3/testsuite/27_io/basic_fstream/53984.cc

@@ -0,0 +1,64 @@

+// Copyright (C) 2017 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/>.

+

+// { dg-require-fileio "" }

+

+// PR libstdc++/53984

+

+#include <fstream>

+#include <testsuite_hooks.h>

+

+void

+test01()

+{

+  std::ifstream in(".");

+  if (in)

+  {

+    char c;

+    if (in.get(c))

+    {

+      // Reading a directory doesn't produce an error on this target

+      // so the formatted input functions below wouldn't fail anyway

+      // (see PR libstdc++/81808).

+      return;

+    }

+    int x;

+    in.clear();

+    // Formatted input function should set badbit, but not throw:

+    in >> x;

+    VERIFY( in.bad() );

+

+    in.clear();

+    in.exceptions(std::ios::badbit);

+    try

+    {

+      // Formatted input function should set badbit, and throw:

+      in >> x;

+      VERIFY( false );

+    }

+    catch (const std::exception&)

+    {

+      VERIFY( in.bad() );

+    }

+  }

+}

+

+int

+main()

+{

+  test01();

+}

--- /dev/null

+++ libstdc++-v3/testsuite/27_io/basic_istream/sentry/char/53984.cc

@@ -0,0 +1,41 @@

+// Copyright (C) 2017 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 <streambuf>

+#include <istream>

+#include <testsuite_hooks.h>

+

+struct SB : std::streambuf

+{

+  virtual int_type underflow() { throw 1; }

+};

+

+void

+test01()

+{

+  SB sb;

+  std::istream is(&sb);

+  int i;

+  is >> i;

+  VERIFY( is.bad() );

+}

+

+int

+main()

+{

+  test01();

+}