[Boost-commit] svn:boost r46832 - trunk/boost/units

From: steven_at_[hidden]
Date: 2008-06-28 21:02:43

Author: steven_watanabe
Date: 2008-06-28 21:02:42 EDT (Sat, 28 Jun 2008)
New Revision: 46832
URL: http://svn.boost.org/trac/boost/changeset/46832

Log:
Allow quantities to be constructed from the literal 0
Text files modified: 
   trunk/boost/units/quantity.hpp |    10 ++++++++--                              
   1 files changed, 8 insertions(+), 2 deletions(-)

Modified: trunk/boost/units/quantity.hpp
==============================================================================
--- trunk/boost/units/quantity.hpp	(original)
+++ trunk/boost/units/quantity.hpp	2008-06-28 21:02:42 EDT (Sat, 28 Jun 2008)
@@ -91,6 +91,7 @@
         // base units are not the same as units.
         BOOST_MPL_ASSERT_NOT((detail::is_base_unit<Unit>));
         enum { force_instantiation_of_unit = sizeof(Unit) };
+        typedef void (quantity::*unspecified_null_pointer_constant_type)(int*******);
     public:
         typedef quantity<Unit,Y>                        this_type;
         
@@ -101,6 +102,11 @@
         { 
             BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
         }
+
+        quantity(unspecified_null_pointer_constant_type) : val_() 
+        { 
+            BOOST_UNITS_CHECK_LAYOUT_COMPATIBILITY(this_type, Y);
+        }
         
         quantity(const this_type& source) : val_(source.val_) 
         {
@@ -275,10 +281,10 @@
         this_type& operator/=(const value_type& source) { val_ /= source; return *this; }
     
         /// Construct quantity directly from @c value_type (potentially dangerous).
-        static this_type from_value(const value_type& val)  { return this_type(val); }
+        static this_type from_value(const value_type& val)  { return this_type(val, 0); }
 
     protected:
-        explicit quantity(const value_type& val) : val_(val) { }
+        explicit quantity(const value_type& val, int) : val_(val) { }
         
     private:
         value_type    val_;