| .. _error_code_conventions: |
| |
| Return Codes |
| ************ |
| |
| Zephyr uses the standard codes in :file:`errno.h` for all APIs. |
| |
| As a general rule, ``0`` indicates success; a negative errno.h code indicates |
| an error condition. The table below shows the error code conventions based on |
| device driver use cases, but they can also be applied to other kernel |
| components. |
| |
| +-----------------+------------------------------------------------+ |
| | Code | Meaning | |
| +=================+================================================+ |
| | 0 | Success. | |
| +-----------------+------------------------------------------------+ |
| | -EIO | General failure. | |
| +-----------------+------------------------------------------------+ |
| | -ENOTSUP | Operation is not supported or operation is | |
| | | invalid. | |
| +-----------------+------------------------------------------------+ |
| | -EINVAL | Device configuration is not valid or function | |
| | | argument is not valid. | |
| +-----------------+------------------------------------------------+ |
| | -EBUSY | Device controller is busy. | |
| +-----------------+------------------------------------------------+ |
| | -EACCES | Device controller is not accessible. | |
| +-----------------+------------------------------------------------+ |
| | -ENODEV | Device type is not supported. | |
| +-----------------+------------------------------------------------+ |
| | -EPERM | Device is not configured or operation is not | |
| | | permitted. | |
| +-----------------+------------------------------------------------+ |
| | -ENOSYS | Function is not implemented. | |
| +-----------------+------------------------------------------------+ |
