Use nullptr in pugixml.hpp if available, see #91

src/pugixml.hpp

@@ -111,6 +111,15 @@
 #	endif
 #endif
 
+// If C++ is 2011 or higher, use 'nullptr'
+#ifndef PUGIXML_NULL
+#	if __cplusplus >= 201103
+#		define PUGIXML_NULL nullptr
+#	else
+#		define PUGIXML_NULL 0
+#	endif
+#endif
+
 // Character interface macros
 #ifdef PUGIXML_WCHAR_MODE
 #	define PUGIXML_TEXT(t) L ## t
@@ -661,15 +670,15 @@ namespace pugi
 
 	#ifndef PUGIXML_NO_XPATH
 		// Select single node by evaluating XPath query. Returns first node from the resulting node set.
-		xpath_node select_node(const char_t* query, xpath_variable_set* variables = 0) const;
+		xpath_node select_node(const char_t* query, xpath_variable_set* variables = PUGIXML_NULL) const;
 		xpath_node select_node(const xpath_query& query) const;
 
 		// Select node set by evaluating XPath query
-		xpath_node_set select_nodes(const char_t* query, xpath_variable_set* variables = 0) const;
+		xpath_node_set select_nodes(const char_t* query, xpath_variable_set* variables = PUGIXML_NULL) const;
 		xpath_node_set select_nodes(const xpath_query& query) const;
 
 		// (deprecated: use select_node instead) Select single node by evaluating XPath query.
-		PUGIXML_DEPRECATED xpath_node select_single_node(const char_t* query, xpath_variable_set* variables = 0) const;
+		PUGIXML_DEPRECATED xpath_node select_single_node(const char_t* query, xpath_variable_set* variables = PUGIXML_NULL) const;
 		PUGIXML_DEPRECATED xpath_node select_single_node(const xpath_query& query) const;
 
 	#endif
@@ -1212,7 +1221,7 @@ namespace pugi
 	public:
 		// Construct a compiled object from XPath expression.
 		// If PUGIXML_NO_EXCEPTIONS is not defined, throws xpath_exception on compilation errors.
-		explicit xpath_query(const char_t* query, xpath_variable_set* variables = 0);
+		explicit xpath_query(const char_t* query, xpath_variable_set* variables = PUGIXML_NULL);
 
 		// Constructor
 		xpath_query();