Error Unable to build while Live Coding is active. Exit the editor and game, or press Ctrl+Alt+F11 if iterating on code in the editor or game

UE5からライブコーディングがデフォルトで有効になっている。これが有効なときVSでコンパイルできない。オプションで一時的に無効にして、コンパイルするのが良さそう。

Hi Paper Crane,

Unreal Engine 5 uses Live Coding by default. Things work a little bit differently in Unreal Engine 5 now.

Clicking the Hot Reload button will start live coding in the engine. This is more reliable than Hot Reloading was in Unreal Engine 4. You can make changes to your code in your code editor (Visual Studio), in the .h or .cpp files,  and clicking the Hot Reload button in the editor will initiate Live Coding. You can then see your code changes reflected in the editor. For this to work, you must save your changes in the code editor. Clicking Save All in Visual Studio will do the trick.

It is important to note that Live Coding does not actually compile your Visual Studio project. It just performs the Hot Reload and shows you the changes you made to your code. So the next time you close the Unreal editor, if you never compiled in Visual Studio, those changes will not be visible next time you open the Unreal editor. For this reason, it is recommended that you do an actual compile in Visual Studio each time you close the editor.

Live Coding is a tool designed for you to be able to see your code changes more quickly. It is not an alternative to compiling. To make sure the VS project is compiled, compile in VS.

You cannot compile in VS with the editor open when Live Coding is active. You can disable Live Coding by clicking the compile options icon and unchecking Live Coding Enabled.

I recommend using Live Coding to quickly see your code changes, but periodically close the editor and do a "hard compile" from Visual Studio (close the editor and compile your code in VS).

Stephen