# Variable Context

While you can use most variables in almost any context such as `.conf`, `.bbclass`, `.inc`, and `.bb` files, some variables are often associated with a particular locality or context. This chapter describes some common associations.

## Configuration

The following subsections provide lists of variables whose context is configuration: distribution, machine, and local.

### Distribution (Distro)

This section lists variables whose configuration context is the distribution, or distro.

- `DISTRO`

- `DISTRO_NAME`

- `DISTRO_VERSION`

- `MAINTAINER`

- `PACKAGE_CLASSES`

- `TARGET_OS`

- `TARGET_FPU`

- `TCMODE`

- `TCLIBC`

### Machine

This section lists variables whose configuration context is the machine.

- `TARGET_ARCH`

- `SERIAL_CONSOLES`

- `PACKAGE_EXTRA_ARCHS`

- `IMAGE_FSTYPES`

- `MACHINE_FEATURES`

- `MACHINE_EXTRA_RDEPENDS`

- `MACHINE_EXTRA_RRECOMMENDS`

- `MACHINE_ESSENTIAL_EXTRA_RDEPENDS`

- `MACHINE_ESSENTIAL_EXTRA_RRECOMMENDS`

### Local

This section lists variables whose configuration context is the local configuration through the `local.conf` file.

- `DISTRO`

- `MACHINE`

- `DL_DIR`

- `BBFILES`

- `EXTRA_IMAGE_FEATURES`

- `PACKAGE_CLASSES`

- `BB_NUMBER_THREADS`

- `BBINCLUDELOGS`

- `ENABLE_BINARY_LOCALE_GENERATION`

## Recipes

The following subsections provide lists of variables whose context is recipes: required, dependencies, path, and extra build information.

### Required

This section lists variables that are required for recipes.

- `LICENSE`

- `LIC_FILES_CHKSUM`

- `SRC_URI` - used in recipes that fetch local or remote files.

### Dependencies

This section lists variables that define recipe dependencies.

- `DEPENDS`

- `RDEPENDS`

- `RRECOMMENDS`

- `RCONFLICTS`

- `RREPLACES`

### Paths

This section lists variables that define recipe paths.

- `WORKDIR`

- `S`

- `FILES`

### Extra Build Information

This section lists variables that define extra build information for recipes.

- `EXTRA_OECMAKE`

- `EXTRA_OECONF`

- `EXTRA_OEMAKE`

- `PACKAGES`

- `DEFAULT_PREFERENCE`