⚙️ Lesson 7.2: Config Properties & .ini Files

What Config Is For

Config is for settings that persist between runs but aren't part of a player's save game — project- or machine-level values. Think of the three persistence tools you'll meet this module as a spectrum:

Declaring Config Properties

Mark the class with Config=<FileName> and each persisted property with Config. Unreal reads the values from the matching .ini at load.

// GameSettings.h
UCLASS(Config = Game)   // reads/writes DefaultGame.ini / Saved Game.ini
class MYPROJECT_API UGameSettings : public UObject
{
    GENERATED_BODY()

public:
    // 'Config' marks this property as loaded from / saved to the ini file.
    UPROPERTY(Config, EditAnywhere, Category = "Audio")
    float MasterVolume = 1.0f;

    UPROPERTY(Config, EditAnywhere, Category = "Gameplay")
    int32 Difficulty = 1;

    UPROPERTY(Config, EditAnywhere, Category = "Gameplay")
    bool bShowTutorials = true;
};

The corresponding .ini section is keyed by [Package.Class]:

# In Config/DefaultGame.ini
[/Script/MyProject.GameSettings]
MasterVolume=0.8
Difficulty=2
bShowTutorials=False

The .ini Hierarchy

Config isn't one file — it's a layered hierarchy, where later layers override earlier ones. This is what lets a project ship defaults while a player's machine keeps personal overrides.

Saving Config

Reading happens automatically at load. To persist a change the player made (they turned the volume down), call SaveConfig — it writes the Config properties back to the per-user ini.

void UGameSettings::SetMasterVolume(float NewVolume)
{
    MasterVolume = FMath::Clamp(NewVolume, 0.0f, 1.0f);
    SaveConfig();   // persist to the per-user ini so it survives a restart
}

For direct, ad-hoc access to any ini value, the global GConfig object is available — useful for reading a one-off value without a config class:

float Volume = 1.0f;
GConfig->GetFloat(
    TEXT("/Script/MyProject.GameSettings"), TEXT("MasterVolume"),
    Volume, GGameIni);
// GGameIni is the resolved path to the active Game.ini.

Developer Settings

For settings you want to appear as a page in Project Settings (or Editor Preferences), subclass UDeveloperSettings. It's a config class that Unreal automatically surfaces in the settings UI and makes globally accessible.

#include "Engine/DeveloperSettings.h"

UCLASS(Config = Game, DefaultConfig, meta = (DisplayName = "My Game Settings"))
class MYPROJECT_API UMyGameSettings : public UDeveloperSettings
{
    GENERATED_BODY()

public:
    UPROPERTY(Config, EditAnywhere, Category = "Gameplay")
    float DefaultDifficultyScale = 1.0f;

    // Reach it anywhere:
    static const UMyGameSettings* Get()
    {
        return GetDefault<UMyGameSettings>();
    }
};

Hands-on Exercise & Quiz

Summary

📚 Additional Resources

• Configuration Files (Epic)
• BenUI — UCLASS Config specifiers

🚀 What's Next?

Config persists settings. Next we persist the thing players care about most — their progress. SaveGame: writing and reading a save slot so a player can pick up where they left off.