Merge pull request #101 from zauguin/funcPtr

Support function pointers as callbacks

Author: zauguin

hdr/sqlite_modern_cpp/utility/function_traits.h

@@ -20,17 +20,7 @@ namespace sqlite {
 		>
 		struct function_traits<
 			ReturnType(ClassType::*)(Arguments...) const
-		> {
-			typedef ReturnType result_type;
-
-			template <std::size_t Index>
-			using argument = typename std::tuple_element<
-				Index,
-				std::tuple<Arguments...>
-			>::type;
-
-			static const std::size_t arity = sizeof...(Arguments);
-		};
+		> : function_traits<ReturnType(*)(Arguments...)> { };
 
     /* support the non-const operator ()
      * this will work with user defined functors */
@@ -41,6 +31,14 @@ namespace sqlite {
 		>
 		struct function_traits<
 			ReturnType(ClassType::*)(Arguments...)
+		> : function_traits<ReturnType(*)(Arguments...)> { };
+
+		template <
+			typename    ReturnType,
+			typename... Arguments
+		>
+		struct function_traits<
+			ReturnType(*)(Arguments...)
 		> {
 			typedef ReturnType result_type;
 

tests/functions.cc

@@ -5,6 +5,9 @@
 using namespace  sqlite;
 using namespace std;
 
+int add_integers(int i, int j) {
+	return i+j;
+}
 int main()
 {
 	try
@@ -13,7 +16,7 @@ int main()
 
     db.define("my_new_concat", [](std::string i, std::string j) {return i+j;});
     db.define("my_new_concat", [](std::string i, std::string j, std::string k) {return i+j+k;});
-    db.define("add_integers", [](int i, int j) {return i+j;});
+    db.define("add_integers", &add_integers);
 		std::string test1, test3;
 		int test2 = 0;
 		db << "select my_new_concat('Hello ','world!')" >> test1;