diff --git a/doc/reference.html b/doc/reference.html
index 5671435..d2efbb2 100644
--- a/doc/reference.html
+++ b/doc/reference.html
@@ -458,7 +458,7 @@
       cont error_category &  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>
@@ -523,20 +523,10 @@
   <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
-<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>
+<p><i>Returns:</i> <code>value() != 0</code>.</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 
@@ -566,10 +556,10 @@
       void clear() noexcept;
 
       // observers:
-      int value() const noexcept;
-      const error_category &amp; category() const noexcept;
-      string message() const;
-      operator unspecified-bool-type () const noexcept;
+      int                    value() const noexcept;
+      const error_category&amp;  category() const noexcept;
+      string                 message() const;
+      explicit               operator bool() const noexcept;
 
     private:
       int val_;                      // <i>exposition only</i>
@@ -632,18 +622,9 @@
 <blockquote>
   <p><i>Returns:</i> <code>category().message( value() )</code>.</p>
 </blockquote>
-<pre>operator unspecified-bool-type () const;</pre>
-<blockquote>
-  <p><i>Returns: </i>If <code>value() != 0</code>, returns a value that will 
-  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>
+<pre>explicit operator bool() const noexcept;</pre>
+<blockquote>
+  <p><i>Returns: </i> <code>value() != 0</code>. </p>
 </blockquote>
   <h2><a name="throws-object"><code>throws</code> object</a></h2>
   <pre>extern error_code throws;</pre>
diff --git a/include/boost/system/error_code.hpp b/include/boost/system/error_code.hpp
index b6ff6e4..6ec444f 100644
--- a/include/boost/system/error_code.hpp
+++ b/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,
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index 024cb88..c6008fc 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -26,10 +26,10 @@ 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