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content/blog/clean-config-reply/index.md

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+---
+title: "Getting a clean config directory, with KConfigXT!"
+date: 2023-10-08
+draft: false
+tags:
+- KDE
+- Qt
+- C++
+- Open Source
+---
+
+This is a sort-of reply to [Herzenschein's blog post](https://rabbitictranslator.com/kconfig/) from a few months ago. He goes over how to tell [KConfig](https://api.kde.org/frameworks/kconfig/html/) put it's files into app-specific folders instead of dumping them into the garbage bin of `~/.config`. He noted that he hasn't touched [KConfigXT](https://develop.kde.org/docs/features/configuration/kconfig_xt/) yet, so this is how to make it work with KConfigXT applications.
+
+However you'll notice by default KConfigXT generates constructors for your configuration class like this:
+
+```cpp
+class Config : public KConfigSkeleton
+{
+  Q_OBJECT
+  public:
+
+    Config( QObject *parent );
+    ~Config() override;
+...
+```
+
+That's not useful, and it took me a minute to figure out how to allow KConfigSkeleton and the KConfig compiler to let me pass `AppConfigLocation`. However, the solution is very simple.
+
+First, you need to make sure it's not a `Singleton`. (There's probably a way to make it work with a singleton though.) Make sure that setting is turned off in your `.kcfgc`:
+
+```ini
+File=config.kcfg
+ClassName=Config
+Mutators=true
+DefaultValueGetters=true
+GenerateProperties=true
+Singleton=false
+```
+
+And then in your `.kcfg`, modify the `<kcfgfile>` block to add `arg = "true"` instead of hardcoding a filename. It will look something like this:
+
+```xml
+<kcfgfile arg="true" />
+```
+
+Once you run the compiler again, you'll get a constructor that allows you to pass a KSharedConfig!
+
+```cpp
+class Config : public KConfigSkeleton
+{
+  Q_OBJECT
+  public:
+
+    Config( KSharedConfig::Ptr config = KSharedConfig::openConfig() );
+    ~Config() override;
+...
+```
+
+And then you call the usual function:
+
+```cpp
+new Config(KSharedConfig::openConfig("myappconfigrc", KConfig::SimpleConfig, QStandardPaths::AppConfigLocation));
+```
+
+Now enjoy your configuration file living in it's own directory! Here's the [constructor parameter logic in KConfig](https://invent.kde.org/frameworks/kconfig/-/blob/master/src/kconfig_compiler/KConfigSourceGenerator.cpp?ref_type=heads#L212) which was essential in figuring this out.