Use C++11 explicit conversion operator if available

[SVN r83210]

doc/reference.html

@@ -452,7 +452,7 @@ error_code</code> synopsis</a></h3>
       cont error_category &amp;  category() const noexcept;
       error_condition        default_error_condition() const noexcept;
       string                 message() const;
-      operator unspecified-bool-type() const;
+      explicit               operator bool() const noexcept;
 
     private:
       int val_;                     // <i>exposition only</i>
@@ -517,20 +517,10 @@ error_code</code> observers</a></h3>
   <pre><code>string message() const;</code></pre>
 <blockquote>
 <p><i>Returns:</i>&nbsp; <code>category().message( value())</code>.</p>
-  <p><i>Throws:</i> Nothing.</p>
 </blockquote>
-<pre>operator unspecified-bool-type() const;</pre>
+<pre>explicit operator bool() const noexcept;</pre>
 <blockquote>
-<p><i>Returns:</i> if <code>value() != 0</code>, returns a value that will evaluate
+<p><i>Returns:</i> <code>value() != 0</code>.</p>
-<code>true</code> in a boolean context; otherwise, returns a value that will 
-evaluate <code>false</code> in a boolean context. The value type returned shall 
-not be convertible to <code>int</code>.</p>
-<p><i>Throws:</i> nothing.</p>
-<p><i>[Note: </i>This conversion can be used in contexts where a <code>bool</code> 
-is expected ( e.g., an <code>if</code> condition ); however, implicit conversions 
-( e.g., to <code>int</code>) that can occur with <code>bool</code> are not 
-allowed, eliminating some sources of user error. One possible implementation 
-choice for this type is pointer-to-member. <i>--end note ]</i></p>
 </blockquote>
 <h2><a name="Class-error_condition">Class <code>error_condition</code></a></h2>
 <p>The class <code>error_condition</code> describes an object used to hold 
@@ -560,10 +550,10 @@ implementation specific. <i>--end note ]</i></p>
       void clear() noexcept;
 
       // observers:
-      int value() const noexcept;
+      int                    value() const noexcept;
-      const error_category &amp; category() const noexcept;
+      const error_category&amp;  category() const noexcept;
-      string message() const;
+      string                 message() const;
-      operator unspecified-bool-type () const noexcept;
+      explicit               operator bool() const noexcept;
 
     private:
       int val_;                      // <i>exposition only</i>
@@ -626,18 +616,9 @@ observers</a></h3>
 <blockquote>
   <p><i>Returns:</i> <code>category().message( value() )</code>.</p>
 </blockquote>
-<pre>operator unspecified-bool-type () const;</pre>
+<pre>explicit operator bool() const noexcept;</pre>
 <blockquote>
-  <p><i>Returns: </i>If <code>value() != 0</code>, returns a value that will 
+  <p><i>Returns: </i> <code>value() != 0</code>. </p>
-  evaluate <code>true</code> in a boolean context; otherwise, returns a value 
-  that will evaluate <code>false</code>. The return type shall not be 
-  convertible to <code>int</code>. </p>
-  <p><i>Throws:</i> Nothing.</p>
-  <p><i>&nbsp;[ Note:</i> This conversion can be used in contexts where a <code>bool</code> 
-  is expected ( e.g., an if condition ); however, implicit conversions ( e.g., to
-  <code>int</code>) that can occur with <code>bool</code> are not allowed, 
-  eliminating some sources of user error. One possible implementation choice for 
-  this type is pointer to member. <i>--end note</i> <i>]</i></p>
 </blockquote>
   <h2><a name="throws-object"><code>throws</code> object</a></h2>
   <pre>extern error_code throws;</pre>
@@ -812,7 +793,7 @@ application program interfaces.</p>
 <hr>
 
 <p>Revised 
-<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%B %d, %Y" startspan -->February 27, 2013<!--webbot bot="Timestamp" endspan i-checksum="41547" --> </font>
+<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%B %d, %Y" startspan -->February 28, 2013<!--webbot bot="Timestamp" endspan i-checksum="41551" --> </font>
 </p>
 
 <p><EFBFBD> Copyright Beman Dawes, 2006, 2007, 2008, 2013</p>

include/boost/system/error_code.hpp

@@ -270,6 +270,12 @@ namespace boost
       const error_category &  category() const BOOST_SYSTEM_NOEXCEPT { return *m_cat; }
       std::string             message() const  { return m_cat->message(value()); }
 
+#   ifndef BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
+      explicit operator bool() const BOOST_SYSTEM_NOEXCEPT
+      {
+        return m_val != 0;
+      }
+#   else
       typedef void (*unspecified_bool_type)();
       static void unspecified_bool_true() {}
 
@@ -282,6 +288,7 @@ namespace boost
       {
         return m_val == 0;
       }
+#   endif
 
       // relationals:
       //  the more symmetrical non-member syntax allows enum
@@ -357,6 +364,12 @@ namespace boost
       error_condition         default_error_condition() const BOOST_SYSTEM_NOEXCEPT  { return m_cat->default_error_condition(value()); }
       std::string             message() const  { return m_cat->message(value()); }
 
+#   ifndef BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
+      explicit operator bool() const BOOST_SYSTEM_NOEXCEPT
+      {
+        return m_val != 0;
+      }
+#   else
       typedef void (*unspecified_bool_type)();
       static void unspecified_bool_true() {}
 
@@ -369,6 +382,7 @@ namespace boost
       {
         return m_val == 0;
       }
+#   endif 
 
       // relationals:
       inline friend bool operator==( const error_code & lhs,

test/Jamfile.v2

@@ -25,10 +25,10 @@ project
            : # command line
            : # input files
            : # requirements
-                   <link>static
+             <test-info>always_show_run_output <link>static
          ]
          [ run error_code_test.cpp
-           :  :  : <link>shared : error_code_test_shared
+           :  :  : <test-info>always_show_run_output <link>shared : error_code_test_shared
          ]
          [ run error_code_user_test.cpp
            :  :  : <link>static

test/error_code_test.cpp

@@ -59,6 +59,17 @@ namespace
 int main( int, char ** )
 {
 
+#ifdef BOOST_NO_CXX11_NOEXCEPT
+  std::cout << "BOOST_NO_CXX11_NOEXCEPT is defined" << std::endl;
+#else
+  std::cout << "BOOST_NO_CXX11_NOEXCEPT is not defined" << std::endl;
+#endif
+#ifdef BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
+  std::cout << "BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS is defined" << std::endl;
+#else
+  std::cout << "BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS is not defined" << std::endl;
+#endif
+
   std::cout << "Conversion use cases...\n";
   error_condition x1( errc::file_exists );
   //error_code x2( errc::file_exists ); // should fail to compile

test/system_msvc/system_dll/system_dll.vcxproj

@@ -20,12 +20,14 @@
     <ConfigurationType>DynamicLibrary</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>Unicode</CharacterSet>
+    <PlatformToolset>v110</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>DynamicLibrary</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>Unicode</CharacterSet>
+    <PlatformToolset>v110</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">

test/system_msvc/system_error_test/system_error_test.vcxproj

@@ -20,12 +20,14 @@
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>true</UseDebugLibraries>
     <CharacterSet>Unicode</CharacterSet>
+    <PlatformToolset>v110</PlatformToolset>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
     <ConfigurationType>Application</ConfigurationType>
     <UseDebugLibraries>false</UseDebugLibraries>
     <WholeProgramOptimization>true</WholeProgramOptimization>
     <CharacterSet>Unicode</CharacterSet>
+    <PlatformToolset>v110</PlatformToolset>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
   <ImportGroup Label="ExtensionSettings">