Base Directory

See XDG Base Directory Specification

Regardless of the platform, check the environment variable XDG_XYZ_ABC, If it exists, use the folder defined by the environment variable, Otherwise, use the platform’s default folder

All paths set in these environment variables must be absolute. If an implementation encounters a relative path in any of these variables it should consider the path invalid and ignore it.

Variables that may be used:

• {USER}: Username (Unix-like: environment variable USER, Windows: environment variable USER_NAME)
• {UID}: User ID (Only in Unix-like)
• {APP_NAME}: Application Name
• {APPDATA}: environment variable APPDATA (Only in Windows)
• {LOCALAPPDATA}: environment variable LOCALAPPDATA (Only in Windows)

User-specific Data

XDG: XDG_DATA_HOME:

• Unix-like: ~/.local/share/{APP_NAME}
• Windows: {APPDATA}/{APP_NAME}/data
• MacOS: ~/Library/Application Support/

User-specific Configuration

XDG: XDG_CONFIG_HOME

• Unix-like: ~/.config/{APP_NAME}
• Windows: {APPDATA}/{APP_NAME}/config
• MacOS: ~/Library/Preferences/

User-specific State Data

XDG: XDG_STATE_HOME:

• Unix-like: ~/.local/state/{APP_NAME}
• Windows: {LOCALAPPDATA}/{APP_NAME}/state
• MacOS: ~/Library/Application Support/

User-specific Cached Data

XDG: XDG_CACHE_HOME:

• Unix-like: ~/.cache/{APP_NAME}
• Windows: {LOCALAPPDATA}/{APP_NAME}/cache
• MacOS: ~/Library/Caches/

User-specific Runtime Files

XDG: XDG_RUNTIME_DIR:

• Linux: /run/user/{UID}
• Windows: %TEMP%
• MacOS: $TMPDIR
• Unix-like: /var/run/user/{UID}

System Runtime Files

Similar to this rust: std::env::temp_dir()

• Linux: /tmp
  • Android: Decided by the system
• Windows: GetTempPath2/GetTempPath
• MacOS: confstr(_CS_DARWIN_USER_TEMP_DIR, ...)
• Unix-like: /tmp