Little scopeguard cleanup, and add a test

louloulibs/utils/encoding.cpp

@@ -152,7 +152,7 @@ namespace utils
       throw std::runtime_error("Cannot convert into UTF-8");
 
     // Make sure cd is always closed when we leave this function
-    const auto sg = utils::make_scope_guard([&cd](auto&&){ iconv_close(cd); });
+    const auto sg = utils::make_scope_guard([&cd](){ iconv_close(cd); });
 
     size_t inbytesleft = str.size();
 
@@ -169,7 +169,7 @@ namespace utils
     char* outbuf_ptr = outbuf;
 
     // Make sure outbuf is always deleted when we leave this function
-    const auto sg2 = utils::make_scope_guard([outbuf](auto&&){ delete[] outbuf; });
+    const auto sg2 = utils::make_scope_guard([outbuf](){ delete[] outbuf; });
 
     bool done = false;
     while (done == false)

louloulibs/utils/scopeguard.hpp

@@ -87,9 +87,11 @@ private:
 };
 
 template<typename F>
-auto make_scope_guard(F&& f)
+auto make_scope_guard(F f)
 {
-  return std::unique_ptr<void, std::decay_t<F>>{(void*)1, std::forward<F>(f)};
+  static struct Empty {} empty;
+  auto deleter = [f = std::move(f)](Empty*) { f(); };
+  return std::unique_ptr<Empty, decltype(deleter)>{&empty, std::move(deleter)};
 }
 
 }