so that's how libraries work

CMakeLists.txt

@@ -35,9 +35,11 @@ foreach(cogfile ${cogfiles})
         set(coggedfiles ${coggedfiles} "${thisfile}")
 endforeach(cogfile)
 
+add_library(bottles SHARED ${src}/bottles/bottles.cpp)
+
 add_custom_target(cog ALL DEPENDS ${coggedfiles})
 
 add_executable(cellar ${src}/cellar.cpp ${src}/commands.cpp ${src}/fs.cpp
-        ${src}/bottles.cpp ${src}/version.cpp)
+        ${src}/version.cpp)
 add_dependencies(cellar cog)
-target_link_libraries(cellar ${Boost_LIBRARIES})
+target_link_libraries(cellar ${Boost_LIBRARIES} bottles)

include/bottles.hpp

@@ -5,6 +5,7 @@
 #include <map>
 #include <string>
 
+#include "commands.hpp"
 #include "json.hpp"
 
 using namespace std;
@@ -27,8 +28,11 @@ namespace cellar {
                 string canonical_path;
                 Bottle();
         };
-		map<string, Bottle> get_bottles();
+		extern map<string, Bottle> get_bottles();
 	}
+    namespace commands {
+        extern map<string, cellar::commands::CommandFunction> bottles_commands();
+    }
 }
 
 #endif // __BOTTLES_HPP

include/dll.hpp

@@ -0,0 +1,24 @@
+#if defined _WIN32 || defined __CYGWIN__
+  #ifdef BUILDING_DLL
+    #ifdef __GNUC__
+      #define DLL_PUBLIC __attribute__ ((dllexport))
+    #else
+      #define DLL_PUBLIC __declspec(dllexport) // Note: actually gcc seems to also supports this syntax.
+    #endif
+  #else
+    #ifdef __GNUC__
+      #define DLL_PUBLIC __attribute__ ((dllimport))
+    #else
+      #define DLL_PUBLIC __declspec(dllimport) // Note: actually gcc seems to also supports this syntax.
+    #endif
+  #endif
+  #define DLL_LOCAL
+#else
+  #if __GNUC__ >= 4
+    #define DLL_PUBLIC __attribute__ ((visibility ("default")))
+    #define DLL_LOCAL  __attribute__ ((visibility ("hidden")))
+  #else
+    #define DLL_PUBLIC
+    #define DLL_LOCAL
+  #endif
+#endif

src/bottles/bottles.cpp

@@ -11,11 +11,13 @@
 
 #include "bottles.hpp"
 #include "commands.hpp"
+#include "dll.hpp"
 #include "fs.hpp"
 
 using namespace std;
 using namespace cellar::bottles;
 
+using CommandFunction = cellar::commands::CommandFunction;
 using json = nlohmann::json;
 
 Bottle::Bottle() {
@@ -25,7 +27,7 @@ Bottle::Bottle() {
     type = bottle_anonymous;
 }
 
-map<string, Bottle> cellar::bottles::get_bottles() {
+DLL_PUBLIC map<string, Bottle> cellar::bottles::get_bottles() {
 	map<string, Bottle> result;
 
 	string homepath = getenv("HOME");
@@ -95,4 +97,8 @@ void print_bottles(int argc, char** argv) {
         cout << endl;
     }
 }
-cellar::commands::CommandFunction listcmd = cellar::commands::command_map["list"] = &print_bottles;
+DLL_PUBLIC map<string, CommandFunction> cellar::commands::bottles_commands() {
+    map<string, CommandFunction> result;
+    result.insert(pair<string,CommandFunction>("list", &print_bottles));
+    return result;
+}

src/cellar.cpp

@@ -37,6 +37,10 @@ int main(int argc, char* argv[]) {
 
         cmdparse.parse(argc, argv);
 
+        for (auto item : commands::bottles_commands()) {
+            commands::command_map[item.first] = item.second;
+        }
+
         string usercmd = command.getValue();
         if (commands::command_map.count(usercmd) > 0) {
             commands::command_map[usercmd](argc, argv);