[PATCH, libstdc++-v3] Add newlib specific ctype_members.cc

[PATCH, libstdc++-v3] Add newlib specific ctype_members.cc

[Yufeng Zhang]

Hi,

This patch fixes an issue in the ctype<wchar_t> implementation when the
newlib C library is used.

The generic version of ctype<wchar_t>::_M_convert_to_wmask() in
config/locale/generic/ctype_members.cc assumes that a character type
mask is either a bitmask with only 1 bit set or a bitwise-OR result of
other character type masks; for instance, as illustrated in the C++
Standard 2003 TC1 [lib.category.ctype]:

  enum mask { // numeric values are for exposition only.
    space=1<<0, print=1<<1, cntrl=1<<2, upper=1<<3, lower=1<<4,
    alpha=1<<5, digit=1<<6, punct=1<<7, xdigit=1<<8,
    alnum=alpha|digit, graph=alnum|punct
  };

The newlibc has a more compact character type mask definition; it uses
one byte only to represent the masks:

(newlib/libc/include/ctype.h)
    #define _U 01
    #define _L 02
    #define _N 04
    #define _S 010
    #define _P 020
    #define _C 040
    #define _X 0100
    #define _B 0200

(libstdc++-v3/config/os/newlib/ctype_base.h)
    typedef char mask;
    static const mask upper = _U;
    static const mask lower = _L;
    static const mask alpha = _U | _L;
    static const mask digit = _N;
    static const mask xdigit = _X | _N;
    static const mask space = _S;
    static const mask print = _P | _U | _L | _N | _B;
    static const mask graph = _P | _U | _L | _N;
    static const mask cntrl = _C;
    static const mask punct = _P;
    static const mask alnum = _U | _L | _N;

For _X and _B, the generic version of
ctype<wchar_t>::_M_convert_to_wmask() fails to obtain their
corresponding wmasks, while other ctype_members.cc variants at
config/locale/{gnu,darwin}/ are not capable in handling this case either.

Therefore, in this patch, a newlib specific ctype_members.cc is added
at config/locale/newlib/, and acinclude.m4 is modified to use the new
ctype_members.cc when with_newlib is enabled. The main difference in this
ctype_members.cc from the generic version is the addition of the special
handling of xdigit and print at the end of
ctype<wchar_t>::_M_convert_to_wmask().

With this patch the following test failure (when the C library is the
newlib C) will be fixed:
    libstdc++-v3/testsuite/22_locale/ctype/scan/wchar_t/1.cc.

The patch has passed the regression test with armv7-a arm-eabi on qemu.

Is it OK for trunk?

Thanks,
Yufeng


libstdc++-v3/ChangeLog
2011-06-06  Yufeng Zhang  <yufeng.zhang@arm.com>

        * config/locale/newlib/ctype_members.cc: New file.
        * acinclude.m4 (GLIBCXX_ENABLE_CLOCALE): Add a new C locale
        kind: newlib.  Configure to use the newlib specific
        ctype_members.cc when with_newlib is enabled.
        * configure: Regenerate.

[PING] [PATCH, libstdc++-v3] Add newlib specific ctype_members.cc

[Yufeng Zhang]

Ping for:
http://gcc.gnu.org/ml/gcc-patches/2011-06/msg00440.html


> libstdc++-v3/ChangeLog
> 2011-06-06  Yufeng Zhang  <yufeng.zhang@arm.com>
> 
>         * config/locale/newlib/ctype_members.cc: New file.
>         * acinclude.m4 (GLIBCXX_ENABLE_CLOCALE): Add a new C locale
>         kind: newlib.  Configure to use the newlib specific
>         ctype_members.cc when with_newlib is enabled.
>         * configure: Regenerate.

Re: [PING] [PATCH, libstdc++-v3] Add newlib specific ctype_members.cc

[Paolo Carlini]

Hi,
> Ping for:
> http://gcc.gnu.org/ml/gcc-patches/2011-06/msg00440.html
personally, I have only minor comments, like only 2011 as Copyright year 
for new files, and please also regtest on a gnu-linux system.

Before going ahead, however, you should send the patch also to the 
libstdc++ mailing list (this is the rule for v3 patches) and make sure 
the other maintainers don't have further comments. Wait, say, at least a 
couple of days.

Thanks,
Paolo.

PS: no regenerated files in the diffs.

RE: [PING] [PATCH, libstdc++-v3] Add newlib specific ctype_members.cc

[Yufeng Zhang]

[-- Attachment #1: Type: text/plain, Size: 952 bytes --]

Hi Paolo,

Thank you for the review.

> > Ping for:
> > http://gcc.gnu.org/ml/gcc-patches/2011-06/msg00440.html
> personally, I have only minor comments, like only 2011 as Copyright
> year for new files, and please also regtest on a gnu-linux system.

I've updated the Copyright year and removed the regenerated file from
the patch. The updated patch is attached.

I've also run the regtest on x86_64-linux-gnu.

> Before going ahead, however, you should send the patch also to the
> libstdc++ mailing list (this is the rule for v3 patches) and make sure
> the other maintainers don't have further comments. Wait, say, at least
> a couple of days.

Sorry for missing the rule previously. I sent the patch to the libstdc++
mailing list yesterday; see
http://gcc.gnu.org/ml/libstdc++/2011-06/msg00091.html
I've also added the mailing list to the CC list. I'll wait a few days
to see if there is any more comment.

Thanks,
Yufeng

[-- Attachment #2: patch-add-newlib-specific-ctype-members.cc.txt --]
[-- Type: text/plain, Size: 9811 bytes --]

diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index ed8b129..7f9231c 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -1753,7 +1753,7 @@ dnl
 AC_DEFUN([GLIBCXX_ENABLE_CLOCALE], [
   GLIBCXX_ENABLE(clocale,auto,[[[=MODEL]]],
     [use MODEL for target locale package],
-    [permit generic|gnu|ieee_1003.1-2001|yes|no|auto])
+    [permit generic|gnu|ieee_1003.1-2001|newlib|yes|no|auto])
 
   # Deal with gettext issues.  Default to not using it (=no) until we detect
   # support for it later.  Let the user turn it off via --e/d, but let that
@@ -1764,7 +1764,7 @@ AC_DEFUN([GLIBCXX_ENABLE_CLOCALE], [
     [],
     [enable_nls=yes])
 
-  # Either a known packaage, or "auto"
+  # Either a known package, or "auto"
   if test $enable_clocale = no || test $enable_clocale = yes; then
      enable_clocale=auto
   fi
@@ -1781,7 +1781,11 @@ AC_DEFUN([GLIBCXX_ENABLE_CLOCALE], [
 	enable_clocale_flag=darwin
 	;;
       *)
-	enable_clocale_flag=generic
+	if test x"$with_newlib" = x"yes"; then
+	  enable_clocale_flag=newlib
+	else
+	  enable_clocale_flag=generic
+	fi
 	;;
     esac
   fi
@@ -1915,6 +1919,22 @@ AC_DEFUN([GLIBCXX_ENABLE_CLOCALE], [
       CTIME_CC=config/locale/generic/time_members.cc
       CLOCALE_INTERNAL_H=config/locale/generic/c++locale_internal.h
       ;;
+    newlib)
+      AC_MSG_RESULT(newlib)
+
+      CLOCALE_H=config/locale/generic/c_locale.h
+      CLOCALE_CC=config/locale/generic/c_locale.cc
+      CCODECVT_CC=config/locale/generic/codecvt_members.cc
+      CCOLLATE_CC=config/locale/generic/collate_members.cc
+      CCTYPE_CC=config/locale/newlib/ctype_members.cc
+      CMESSAGES_H=config/locale/generic/messages_members.h
+      CMESSAGES_CC=config/locale/generic/messages_members.cc
+      CMONEY_CC=config/locale/generic/monetary_members.cc
+      CNUMERIC_CC=config/locale/generic/numeric_members.cc
+      CTIME_H=config/locale/generic/time_members.h
+      CTIME_CC=config/locale/generic/time_members.cc
+      CLOCALE_INTERNAL_H=config/locale/generic/c++locale_internal.h
+      ;;
   esac
 
   # This is where the testsuite looks for locale catalogs, using the
diff --git a/libstdc++-v3/config/locale/newlib/ctype_members.cc b/libstdc++-v3/config/locale/newlib/ctype_members.cc
new file mode 100644
index 0000000..ee91baf
--- /dev/null
+++ b/libstdc++-v3/config/locale/newlib/ctype_members.cc
@@ -0,0 +1,280 @@
+// std::ctype implementation details, newlib version -*- C++ -*-
+
+// Copyright (C) 2011 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.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+//
+// ISO C++ 14882: 22.2.1.1.2  ctype virtual functions.
+//
+
+#include <locale>
+#include <cstdlib>
+#include <cstring>
+#include <cstdio>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  // NB: The other ctype<char> specializations are in src/locale.cc and
+  // various /config/os/* files.
+  ctype_byname<char>::ctype_byname(const char* __s, size_t __refs)
+  : ctype<char>(0, false, __refs)
+  {
+    if (std::strcmp(__s, "C") != 0 && std::strcmp(__s, "POSIX") != 0)
+      {
+	this->_S_destroy_c_locale(this->_M_c_locale_ctype);
+	this->_S_create_c_locale(this->_M_c_locale_ctype, __s);
+      }
+  }
+
+  ctype_byname<char>::~ctype_byname()
+  { }
+
+#ifdef _GLIBCXX_USE_WCHAR_T
+  ctype<wchar_t>::__wmask_type
+  ctype<wchar_t>::_M_convert_to_wmask(const mask __m) const throw()
+  {
+    __wmask_type __ret;
+    switch (__m)
+      {
+      case space:
+	__ret = wctype("space");
+	break;
+      case print:
+	__ret = wctype("print");
+	break;
+      case cntrl:
+	__ret = wctype("cntrl");
+	break;
+      case upper:
+	__ret = wctype("upper");
+	break;
+      case lower:
+	__ret = wctype("lower");
+	break;
+      case alpha:
+	__ret = wctype("alpha");
+	break;
+      case digit:
+	__ret = wctype("digit");
+	break;
+      case punct:
+	__ret = wctype("punct");
+	break;
+      case xdigit:
+	__ret = wctype("xdigit");
+	break;
+      case alnum:
+	__ret = wctype("alnum");
+	break;
+      case graph:
+	__ret = wctype("graph");
+	break;
+      default:
+	// Different from the generic version, xdigit and print in
+	// newlib are defined as bitwise-OR result of bitmasks:
+	//   xdigit = _X | _N;
+	//   print  = _P | _U | _L | _N | _B;
+	// in which _X and _B don't correspond to any ctype mask.
+	// In order to get the wmask correctly converted when __m is
+	// equal to _X or _B, the two cases are specifically handled
+	// here.
+	if (__m & xdigit)
+	  __ret = wctype("xdigit");
+	else if (__m & print)
+	  __ret = wctype("print");
+	else
+	  __ret = __wmask_type();
+      }
+    return __ret;
+  };
+
+  wchar_t
+  ctype<wchar_t>::do_toupper(wchar_t __c) const
+  { return towupper(__c); }
+
+  const wchar_t*
+  ctype<wchar_t>::do_toupper(wchar_t* __lo, const wchar_t* __hi) const
+  {
+    while (__lo < __hi)
+      {
+        *__lo = towupper(*__lo);
+        ++__lo;
+      }
+    return __hi;
+  }
+
+  wchar_t
+  ctype<wchar_t>::do_tolower(wchar_t __c) const
+  { return towlower(__c); }
+
+  const wchar_t*
+  ctype<wchar_t>::do_tolower(wchar_t* __lo, const wchar_t* __hi) const
+  {
+    while (__lo < __hi)
+      {
+        *__lo = towlower(*__lo);
+        ++__lo;
+      }
+    return __hi;
+  }
+
+  bool
+  ctype<wchar_t>::
+  do_is(mask __m, wchar_t __c) const
+  {
+    bool __ret = false;
+    // Newlib C library has a compact encoding that uses 8 bits only.
+    const size_t __bitmasksize = 7;
+    for (size_t __bitcur = 0; __bitcur <= __bitmasksize; ++__bitcur)
+      if (__m & _M_bit[__bitcur]
+	  && iswctype(__c, _M_wmask[__bitcur]))
+	{
+	  __ret = true;
+	  break;
+	}
+    return __ret;
+  }
+
+  const wchar_t*
+  ctype<wchar_t>::
+  do_is(const wchar_t* __lo, const wchar_t* __hi, mask* __vec) const
+  {
+    for (; __lo < __hi; ++__vec, ++__lo)
+      {
+	// Newlib C library has a compact encoding that uses 8 bits only.
+	const size_t __bitmasksize = 7;
+	mask __m = 0;
+	for (size_t __bitcur = 0; __bitcur <= __bitmasksize; ++__bitcur)
+	  if (iswctype(*__lo, _M_wmask[__bitcur]))
+	    __m |= _M_bit[__bitcur];
+	*__vec = __m;
+      }
+    return __hi;
+  }
+
+  const wchar_t*
+  ctype<wchar_t>::
+  do_scan_is(mask __m, const wchar_t* __lo, const wchar_t* __hi) const
+  {
+    while (__lo < __hi && !this->do_is(__m, *__lo))
+      ++__lo;
+    return __lo;
+  }
+
+  const wchar_t*
+  ctype<wchar_t>::
+  do_scan_not(mask __m, const char_type* __lo, const char_type* __hi) const
+  {
+    while (__lo < __hi && this->do_is(__m, *__lo) != 0)
+      ++__lo;
+    return __lo;
+  }
+
+  wchar_t
+  ctype<wchar_t>::
+  do_widen(char __c) const
+  { return _M_widen[static_cast<unsigned char>(__c)]; }
+
+  const char*
+  ctype<wchar_t>::
+  do_widen(const char* __lo, const char* __hi, wchar_t* __dest) const
+  {
+    while (__lo < __hi)
+      {
+	*__dest = _M_widen[static_cast<unsigned char>(*__lo)];
+	++__lo;
+	++__dest;
+      }
+    return __hi;
+  }
+
+  char
+  ctype<wchar_t>::
+  do_narrow(wchar_t __wc, char __dfault) const
+  {
+    if (__wc >= 0 && __wc < 128 && _M_narrow_ok)
+      return _M_narrow[__wc];
+    const int __c = wctob(__wc);
+    return (__c == EOF ? __dfault : static_cast<char>(__c));
+  }
+
+  const wchar_t*
+  ctype<wchar_t>::
+  do_narrow(const wchar_t* __lo, const wchar_t* __hi, char __dfault,
+	    char* __dest) const
+  {
+    if (_M_narrow_ok)
+      while (__lo < __hi)
+	{
+	  if (*__lo >= 0 && *__lo < 128)
+	    *__dest = _M_narrow[*__lo];
+	  else
+	    {
+	      const int __c = wctob(*__lo);
+	      *__dest = (__c == EOF ? __dfault : static_cast<char>(__c));
+	    }
+	  ++__lo;
+	  ++__dest;
+	}
+    else
+      while (__lo < __hi)
+	{
+	  const int __c = wctob(*__lo);
+	  *__dest = (__c == EOF ? __dfault : static_cast<char>(__c));
+	  ++__lo;
+	  ++__dest;
+	}
+    return __hi;
+  }
+
+  void
+  ctype<wchar_t>::_M_initialize_ctype() throw()
+  {
+    wint_t __i;
+    for (__i = 0; __i < 128; ++__i)
+      {
+	const int __c = wctob(__i);
+	if (__c == EOF)
+	  break;
+	else
+	  _M_narrow[__i] = static_cast<char>(__c);
+      }
+    if (__i == 128)
+      _M_narrow_ok = true;
+    else
+      _M_narrow_ok = false;
+    for (size_t __i = 0;
+	 __i < sizeof(_M_widen) / sizeof(wint_t); ++__i)
+      _M_widen[__i] = btowc(__i);
+
+    for (size_t __i = 0; __i <= 7; ++__i)
+      {
+	_M_bit[__i] = static_cast<mask>(1 << __i);
+	_M_wmask[__i] = _M_convert_to_wmask(_M_bit[__i]);
+      }
+  }
+#endif //  _GLIBCXX_USE_WCHAR_T
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace

RE: [PING] [PATCH, libstdc++-v3] Add newlib specific ctype_members.cc

[Yufeng Zhang]

Hi Paolo,

> -----Original Message-----
> From: gcc-patches-owner@gcc.gnu.org [mailto:gcc-patches-
> owner@gcc.gnu.org] On Behalf Of Yufeng Zhang
> Sent: 01 July 2011 18:00
> To: 'Paolo Carlini'
> Cc: gcc-patches@gcc.gnu.org; libstdc++@gcc.gnu.org
> Subject: RE: [PING] [PATCH, libstdc++-v3] Add newlib specific
> ctype_members.cc
> 
> Hi Paolo,
> 
> Thank you for the review.
> 
> > > Ping for:
> > > http://gcc.gnu.org/ml/gcc-patches/2011-06/msg00440.html
> > personally, I have only minor comments, like only 2011 as Copyright
> > year for new files, and please also regtest on a gnu-linux system.
> 
> I've updated the Copyright year and removed the regenerated file from
> the patch. The updated patch is attached.
> 
> I've also run the regtest on x86_64-linux-gnu.
> 
> > Before going ahead, however, you should send the patch also to the
> > libstdc++ mailing list (this is the rule for v3 patches) and make
> sure
> > the other maintainers don't have further comments. Wait, say, at
> least
> > a couple of days.
> 
> Sorry for missing the rule previously. I sent the patch to the
> libstdc++
> mailing list yesterday; see
> http://gcc.gnu.org/ml/libstdc++/2011-06/msg00091.html
> I've also added the mailing list to the CC list. I'll wait a few days
> to see if there is any more comment.

There is no more comment received. I wonder if it is OK to get the patch
committed. I have write after approval to GCC, but I'm not sure if that
applies to libstdc++-v3 or not. If you think the patch is OK, can you
please help me commit it? If you think I can/shall commit it by myself,
please let me know.


Thanks,
Yufeng

P.S. I have re-verified the patch on the tip of the trunk today.

Re: [PING] [PATCH, libstdc++-v3] Add newlib specific ctype_members.cc

[Paolo Carlini]

On 07/15/2011 07:30 PM, Yufeng Zhang wrote:
> There is no more comment received. I wonder if it is OK to get the 
> patch committed.
What else? I thought you had already committed it ;)

Paolo.

Re: [PING] [PATCH, libstdc++-v3] Add newlib specific ctype_members.cc

[Jonathan Wakely]

[-- Attachment #1: Type: text/plain, Size: 446 bytes --]

On 19 October 2012 18:04, Yufeng Zhang wrote:
>
> Please find the attached patch which documents the 'newlib' option for the
> configuration option '--enable-clocale'.
>
> Feel free to improve it.

Thanks for the description.  I changed it slightly as I realised the
'darwin' option was also undocumented, so I committed the attached
patch to the trunk.

I haven't regenerated the HTML pages, I plan to do that soon after a
few more doc updates.

[-- Attachment #2: patch.txt --]
[-- Type: text/plain, Size: 5044 bytes --]

commit 7e0b461312a4304d8f84602732aa19cb718af32c
Author: Jonathan Wakely <jwakely.gcc@gmail.com>
Date:   Mon Oct 22 00:40:07 2012 +0100

    2012-10-22  Yufeng Zhang  <yufeng.zhang@arm.com>
    	    Jonathan Wakely  <jwakely.gcc@gmail.com>
    
    	* doc/xml/manual/configure.xml (--enable-clocale): Document the
    	'newlib' and 'darwin' options. Minor stylistic improvements.

diff --git a/libstdc++-v3/doc/xml/manual/configure.xml b/libstdc++-v3/doc/xml/manual/configure.xml
index bc98d7a..827b232 100644
--- a/libstdc++-v3/doc/xml/manual/configure.xml
+++ b/libstdc++-v3/doc/xml/manual/configure.xml
@@ -38,7 +38,7 @@
 </para>
 <para>The canonical way to find out the configure options that are
    available for a given set of libstdc++ sources is to go to the
-   source directory and then type:<command>./configure --help</command>.
+   source directory and then type: <command>./configure --help</command>.
 </para>
 
 <variablelist>
@@ -107,15 +107,20 @@
 	(IEEE Std. 1003.1-2001) model based on langinfo/iconv/catgets,
 	'gnu' to specify a model based on functionality from the GNU C
 	library (langinfo/iconv/gettext) (from <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://sources.redhat.com/glibc/">glibc</link>, the GNU C
-	library), or 'generic' to use a generic "C"
-	abstraction which consists of "C" locale info.
+	library), 'generic' to use a generic "C" abstraction which consists
+	of "C" locale info, 'newlib' to specify the Newlib C library model
+	which only differs from the 'generic' model in the handling of
+	ctype, or 'darwin' which omits the <type>wchar_t</type> specializations
+	needed by the 'generic' model.
      </para>
 
-     <para>If not explicitly specified, the configure proccess tries
+     <para>If not explicitly specified, the configure process tries
       to guess the most suitable package from the choices above. The
       default is 'generic'. On glibc-based systems of sufficient
-      vintage (2.3 and newer), 'gnu' is automatically selected. This option
-      can change the library ABI.
+      vintage (2.3 and newer), 'gnu' is automatically selected. On newlib-based
+      systems (<code>'--with_newlib=yes'</code>) and OpenBSD, 'newlib' is
+      automatically selected. On Mac OS X 'darwin' is automatically selected.
+      This option can change the library ABI.
      </para>
  </listitem></varlistentry>
 
@@ -181,9 +186,9 @@
 	and of the nanosleep and sched_yield functions, used in the
 	implementation of [thread.thread.this] of the 2011 ISO C++ standard.
 	The choice OPTION=yes checks for the availability of the facilities
-	in libc and libposix4.  In case of need the latter is also linked
+	in libc and libposix4.  In case it's needed the latter is also linked
 	to libstdc++ as part of the build process.  OPTION=rt also searches
-	(and, in case, links) librt.   Note that the latter is not always
+	(and, if needed, links) librt.   Note that the latter is not always
 	desirable because, in glibc, for example, in turn it triggers the
 	linking of libpthread too, which activates locking, a large overhead
 	for single-thread programs.  OPTION=no skips the tests completely.
@@ -249,7 +254,7 @@
  </listitem></varlistentry>
 
  <varlistentry><term><code>--enable-c99</code></term>
- <listitem><para>The "long long" type was introduced in C99, along
+ <listitem><para>The <type>long long</type> type was introduced in C99, along
 	with many other functions for wide characters, and math
 	classification macros, etc.  If enabled, all C99 functions not
 	specified by the C++ standard will be put into <code>namespace
@@ -264,7 +269,7 @@
  </listitem></varlistentry>
 
  <varlistentry><term><code>--enable-wchar_t</code>[default]</term>
- <listitem><para>Template specializations for the "wchar_t" type are
+ <listitem><para>Template specializations for the <type>wchar_t</type> type are
 	required for wide character conversion support.  Disabling
 	wide character specializations may be expedient for initial
 	porting efforts, but builds only a subset of what is required by
@@ -274,7 +279,7 @@
  </listitem></varlistentry>
 
  <varlistentry><term><code>--enable-long-long  </code></term>
- <listitem><para>The "long long" type was introduced in C99.  It is
+ <listitem><para>The <type>long long</type> type was introduced in C99.  It is
 	provided as a GNU extension to C++98 in g++.  This flag builds
 	support for "long long" into the library (specialized
 	templates and the like for iostreams).  This option is on by default:
@@ -351,7 +356,7 @@
  <listitem><para>Use extern template to pre-instantiate all required
  	specializations for certain types defined in the standard libraries. 
 	These types include <classname>string</classname> and dependents like
-	<classname>char_traits</classname>, the templateized io classes,
+	<classname>char_traits</classname>, the templatized IO classes,
 	<classname>allocator</classname>, and others.  
 	Disabling means that implicit
 	template generation will be used when compiling these types.  By