| name | jna |
| description | Implement or debug JNA bindings in Kotlin or Java, including structures, JVM visibility, callbacks, pointers, ABI layouts, and native-library tests. |
JNA bindings
Treat every mapping as an ABI contract. Verify the native declaration, target architectures, and ownership rules before changing Kotlin or Java code.
Reuse existing mappings
Search JNA Platform and the repository before declaring a native type. Prefer a maintained platform mapping when its field types, alignment, and calling convention match the target API.
Keep reflected types accessible
JNA reflects mapped classes and fields while deriving layouts and invoking callbacks. Make every Structure, Union, callback, and related declaring class JVM-accessible from com.sun.jna:
- In Kotlin, use
internal or public mapped classes; never use private, local, or anonymous mapped classes.
- Keep the mapped class's enclosing chain accessible too.
- Expose structure fields as real public JVM fields, normally with
@JvmField.
- Do not assume public fields compensate for a non-public declaring class. Layout can fail with
IllegalAccessException from Structure.getFieldValue.
Prefer moving visibility only as far as needed over suppressing reflection errors or opening accessibility globally.
Match the native ABI
- Declare structure fields in native order and use
@Structure.FieldOrder.
- Map fixed-width integers, pointers,
size_t, native booleans, wide strings, and platform-dependent numeric types deliberately. Do not infer their size from Kotlin or Java names.
- Model embedded values with
Structure.ByValue; model pointers separately with Pointer or the appropriate reference type.
