improve dynamic loading example

Author: jll63

doc/modules/ROOT/examples/shared_libs/CMakeLists.txt

@@ -9,7 +9,7 @@ message(STATUS "Building dynamic_shared loading examples")
 # dynamic loading, direct virtual_ptrs
 
 add_library(shared SHARED overriders.cpp tiger.cpp)
-target_link_libraries(shared Boost::openmethod)
+target_link_libraries(shared Boost::openmethod Boost::dll)
 set_target_properties(shared PROPERTIES ENABLE_EXPORTS ON)
 
 add_executable(dynamic dynamic_main.cpp)
@@ -24,7 +24,7 @@ add_test(NAME dynamic_shared COMMAND dynamic)
 add_library(indirect_shared SHARED indirect_overriders.cpp indirect_tiger.cpp)
 target_compile_definitions(
     indirect_shared PUBLIC BOOST_OPENMETHOD_DEFAULT_REGISTRY=indirect_registry)
-target_link_libraries(indirect_shared Boost::openmethod)
+target_link_libraries(indirect_shared Boost::openmethod Boost::dll)
 set_target_properties(indirect_shared PROPERTIES ENABLE_EXPORTS ON)
 
 add_executable(indirect indirect_main.cpp)

doc/modules/ROOT/examples/shared_libs/dynamic_main.cpp

@@ -33,6 +33,15 @@ BOOST_OPENMETHOD_OVERRIDE(
 // end::main[]
 
 // tag::before_dlopen[]
+
+#ifndef LIBRARY_NAME
+#ifdef _MSC_VER
+#define LIBRARY_NAME "shared.dll"
+#else
+#define LIBRARY_NAME "libshared.so"
+#endif
+#endif
+
 auto main() -> int {
     using namespace boost::openmethod::aliases;
 
@@ -48,7 +57,7 @@ auto main() -> int {
     }
 
     boost::dll::shared_library lib(
-        boost::dll::program_location().parent_path() / "libshared.so",
+        boost::dll::program_location().parent_path() / LIBRARY_NAME,
         boost::dll::load_mode::rtld_now);
 
     std::cout << "\nAfter loading the shared library.\n";
@@ -62,7 +71,7 @@ auto main() -> int {
         std::cout << "Gracie meets Willy -> " << meet(*gracie, *willy) << "\n";
         std::cout << "Willy meets Gracie -> " << meet(*willy, *gracie) << "\n";
 
-        auto make_tiger = lib.get<Animal*()>("make_tiger");
+        auto make_tiger = lib.get_alias<Animal*()>("make_tiger");
         std::unique_ptr<Animal> hobbes{make_tiger()};
         std::cout << "Gracie meets Tiger -> " << meet(*gracie, *hobbes) << "\n";
     }

doc/modules/ROOT/examples/shared_libs/indirect_main.cpp

@@ -20,6 +20,12 @@
 
 using namespace boost::openmethod::aliases;
 
+#ifdef _MSC_VER
+#define LIBRARY_NAME "indirect_shared.dll"
+#else
+#define LIBRARY_NAME "libindirect_shared.so"
+#endif
+
 struct Cow : Herbivore {};
 struct Wolf : Carnivore {};
 
@@ -46,7 +52,7 @@ auto main() -> int {
     std::cout << "Willy meets Gracie -> " << meet(*willy, *gracie) << "\n";
 
     boost::dll::shared_library lib(
-        boost::dll::program_location().parent_path() / "libindirect_shared.so",
+        boost::dll::program_location().parent_path() / LIBRARY_NAME,
         boost::dll::load_mode::rtld_now);
 
     std::cout << "\nAfter loading the shared library.\n";
@@ -57,7 +63,7 @@ auto main() -> int {
     std::cout << "Willy meets Gracie -> " << meet(*willy, *gracie) << "\n";
 
     {
-        auto make_tiger = lib.get<Animal*()>("make_tiger");
+        auto make_tiger = lib.get_alias<Animal*()>("make_tiger");
         std::unique_ptr<Animal> hobbes{make_tiger()};
         std::cout << "Gracie meets Tiger -> " << meet(*gracie, *hobbes) << "\n";
     }

doc/modules/ROOT/examples/shared_libs/overriders.cpp

@@ -24,12 +24,4 @@ BOOST_OPENMETHOD_OVERRIDE(
     return "hunt";
 }
 
-struct Tiger : Carnivore {};
-
-BOOST_OPENMETHOD_CLASSES(Tiger, Carnivore);
-
-extern "C" auto make_tiger() -> Tiger* {
-    return new Tiger;
-}
-
 // end::dl_shared[]

include/boost/openmethod/initialize.hpp

@@ -1273,7 +1273,7 @@ void registry<Policies...>::compiler<Options...>::write_global_data() {
         });
     dispatch_data_size = std::accumulate(
         classes.begin(), classes.end(), dispatch_data_size,
-        [](auto sum, const auto& cls) { return sum + cls.vtbl.size(); });
+        [](auto sum, auto& cls) { return sum + cls.vtbl.size(); });
 
     std::vector<detail::word> new_dispatch_data(dispatch_data_size);
     auto gv_first = new_dispatch_data.data();