inherit from std::iterator<> to add some typedefs that make GNU G++ happy. Unfortunately, std::iterator<> is deprecated in C++17, for whatever reason. :-/

src/wrapper.hh

@@ -5,6 +5,7 @@
 #define LIBPEPDATATYPES_WRAPPER_HH
 
 #include <initializer_list>
+#include <iterator>
 
 namespace pEp
 {
@@ -129,14 +130,15 @@ public:
     static Element T::* const Value; // to access the current value
     
     // does not own the *value
-    class iterator
+    class iterator : public std::iterator< std::forward_iterator_tag, Element, ptrdiff_t>
     {
     public:
+    
         iterator() = default;
         
-        iterator operator++()  { return (value ? value = value->next : value); }
-        Element   operator*()  { return value->*LW::Value; }
-        Element  operator->() { return (value->*LW::Value); }
+        iterator operator++() { return (value ? value = value->next : value); }
+        Element  operator*()  { return value->*LW::Value; }
+        Element  operator->() { return value->*LW::Value; }
         bool     operator==(const iterator& other) const { return value == other.value; }
         bool     operator!=(const iterator& other) const { return value != other.value; }