# E0055

Warning name: `unannotated_ffi`

Unannotated FFI param type.

The FFI parameter of pointer type should be annotated with either `#borrow` or\
`#owned`, the default calling convention is currently `#owned` and it will be\
changed in the future. For the detailed meaning, checkout
[FFI documentation](/language/ffi.md#the-borrow-and-owned-attribute).

## Erroneous example

```{literalinclude} /sources/error_codes/0055_error/top.mbt
:language: moonbit
```

## Suggestion

Add the missing `#borrow` or `#owned` annotation.

```{literalinclude} /sources/error_codes/0055_fixed/top.mbt
:language: moonbit
```