c++ steps

Author: UnixY2K

README.md

@@ -2,7 +2,7 @@
 
 App Center Interop example for c++/c#(winforms).
 
-## C# Steps
+## C# first Steps
 
 - Create a new C# project.
    ```sh
@@ -37,3 +37,13 @@ App Center Interop example for c++/c#(winforms).
       AppCenter.Start("{Your App Secret}", typeof(Analytics), typeof(Crashes));
   }    
   ```
+
+
+## C++ Steps
+
+Basically, you need to create a new or use an existing `C++ project`
+so you can build a dll that will contain your code that get called from the `C# project`.
+
+For demonstration purposes we will use meson/ninja to create a new `C++ project` and clang or msvc to compile it, but you can use your preferred toolchain (for example CMake) to build the dll.
+
+in this example project it will show a dialog box for simplicity.

cpp/include/dialogBox.hpp

@@ -0,0 +1,6 @@
+#pragma once
+
+// example dialog box snippet
+#include <string>
+
+void showDialogBox(std::string title, std::string message);

cpp/include/exportAPI.hpp

@@ -0,0 +1,22 @@
+#pragma once
+
+#if defined(myAppLIBRARY_EXPORT)
+#   define myAppAPI EXPORT
+#else
+#   define myAppAPI IMPORT
+#endif
+
+#if defined(_MSC_VER)
+    //  Microsoft 
+    #define EXPORT __declspec(dllexport)
+    #define IMPORT __declspec(dllimport)
+#elif defined(__GNUC__)
+    //  GCC
+    #define EXPORT __attribute__((visibility("default")))
+    #define IMPORT
+#else
+    //  do nothing
+    #define EXPORT
+    #define IMPORT
+    #pragma warning Unknown dynamic link import/export semantics.
+#endif

cpp/meson.build

@@ -0,0 +1,33 @@
+myApp_inc = include_directories('include')
+
+myApp_sources = [
+    'src/main.cpp',
+    'src/dialogBox.cpp',
+]
+myApp_args = []
+myApp_link = []
+myApp_deps = []
+
+
+if host_machine.system() == 'linux'
+    message('Building for Linux')
+    gtkmm_dep = dependency('gtkmm-3.0')
+    myApp_deps += [gtkmm_dep]
+endif
+
+
+# we compile the c++ application as a shared library
+myApp_lib = library('myapp',
+                        myApp_sources,
+                        include_directories : myApp_inc,
+                        cpp_args: myApp_args,
+                        dependencies : myApp_deps)
+
+# we compile the c++ application as a standalone executable
+# for development/debugging purposes
+myApp_exe = executable('myApp',
+                            myApp_sources,
+                            include_directories: myApp_inc,
+                            cpp_args: myApp_args,
+                            dependencies: myApp_deps,
+                            link_with: myApp_link)

cpp/src/dialogBox.cpp

@@ -0,0 +1,30 @@
+#include <dialogBox.hpp>
+#ifdef _WIN32
+// windows message box
+#include <windows.h>
+#endif
+// for linux we use gtkmm 3.0
+#ifdef __linux__
+#include <gtkmm/messagedialog.h>
+#endif
+
+void showDialogBox(std::string title, std::string message) {
+// windows message box
+#ifdef _WIN32
+    MessageBox(NULL, message.c_str(), title.c_str(), MB_OK);
+#endif
+// linux message box
+#ifdef __linux__
+    auto app = Gtk::Application::create("com.example.myapp");
+	Gtk::MessageDialog dialog(title, false, Gtk::MESSAGE_INFO);
+    dialog.set_secondary_text(message);
+    // close the dialog when the user clicks the OK button
+    dialog.signal_response().connect([&dialog, &app](int) {
+        // close the dialog
+        dialog.close();
+        // exit the application
+        app->quit();
+    });
+    app->run(dialog);
+#endif
+}

cpp/src/main.cpp

@@ -0,0 +1,17 @@
+#include <dialogBox.hpp>
+#include <iostream>
+
+#define myAppLIBRARY_EXPORT
+#include <exportAPI.hpp>
+
+// your main code
+int main() {
+	std::cout << "C++ Powered\n";
+	showDialogBox("C++ Powered", "Hello from C++!");
+}
+// the entry point of your program
+// you need to export this function
+
+extern "C" {
+myAppAPI void dllEntry() { main(); }
+}

meson.build

@@ -0,0 +1,9 @@
+project(
+    'myApp', 'cpp',
+    default_options: ['cpp_std=c++17'],
+    version: '1.0.0 v2022',
+    license: 'BSD-3'
+)
+version = '1.0.0 v2022'
+
+subdir('cpp')