make symbol visibility=hidden by default

Jamroot.jam

@@ -18,12 +18,14 @@ project logsys
 
 	<toolset>gcc:<cxxflags>-std=c++1z
 	<toolset>gcc:<cxxflags>-fconstexpr-depth=1024
+	<toolset>gcc:<cxxflags>-fvisibility=hidden
 	<toolset>gcc:<cxxflags>-Wall
 	<toolset>gcc:<cxxflags>-Wextra
 	<toolset>gcc:<linkflags>-lpthread
 
 	<toolset>clang:<cxxflags>-std=c++1z
 	<toolset>clang:<cxxflags>-fconstexpr-depth=1024
+	<toolset>clang:<cxxflags>-fvisibility=hidden
 	<toolset>clang:<cxxflags>-Wall
 	<toolset>clang:<cxxflags>-Wextra
 	<toolset>clang:<cxxflags>-stdlib=libc++

include/logsys/stdlogb.hpp

@@ -9,6 +9,8 @@
 #ifndef _logsys__stdlogb__hpp_INCLUDED_
 #define _logsys__stdlogb__hpp_INCLUDED_
 
+#include <boost/config.hpp>
+
 #include <iostream>
 #include <memory>
 
@@ -17,14 +19,12 @@ namespace logsys{
 
 
 	/// \brief Base class for dynamic log tag classes
-	class stdlogb{
+	class BOOST_SYMBOL_EXPORT stdlogb{
 	public:
 		/// \brief Create a stdlogb derived log object
 		///
-		/// There are two ways to use this function:
-		///   1. You can just include the header and write your own definition.
-		///   2. You can link agains logsys/liblogsys.so and assign your log
-		///      object creater function to stdlogb_factory_object.
+		/// Link against logsys/liblogsys.so and assign your log object creater
+		/// function to stdlogb_factory_object.
 		static std::unique_ptr< stdlogb > factory()noexcept;
 
 		/// \brief Destructor

include/logsys/stdlogb_factory_object.hpp

@@ -9,6 +9,8 @@
 #ifndef _logsys__stdlogb_factory_object__hpp_INCLUDED_
 #define _logsys__stdlogb_factory_object__hpp_INCLUDED_
 
+#include <boost/config.hpp>
+
 #include <memory>
 #include <functional>
 
@@ -19,7 +21,8 @@ namespace logsys{
 	class stdlogb;
 
 	/// \brief Assign your log object maker to this variable
-	extern std::function< std::unique_ptr< stdlogb >() > stdlogb_factory_object;
+	extern BOOST_SYMBOL_EXPORT
+	std::unique_ptr< stdlogb >(*stdlogb_factory_object)()noexcept;
 
 
 }

src/stdlogb.cpp

@@ -9,11 +9,14 @@
 #include <logsys/stdlogb_factory_object.hpp>
 #include <logsys/stdlogb.hpp>
 
+#include <cassert>
+
 
 namespace logsys{
 
 
 	std::unique_ptr< stdlogb > stdlogb::factory()noexcept try{
+		assert(stdlogb_factory_object != nullptr);
 		return stdlogb_factory_object();
 	}catch(std::exception const& e){
 		std::cerr << "terminate with exception in stdlogb factory: "

src/stdlogb_factory_object.cpp

@@ -13,9 +13,10 @@
 namespace logsys{
 
 
-	std::function< std::unique_ptr< stdlogb >() > stdlogb_factory_object(
-		[](){ return std::make_unique< stdlogd >(); }
-	);
+	std::unique_ptr< stdlogb >(*stdlogb_factory_object)()noexcept =
+		[]()noexcept->std::unique_ptr< stdlogb >{
+			return std::make_unique< stdlogd >();
+		};
 
 
 }