Macro table_scan_callback 

macro_rules! table_scan_callback {
    ($name:ident, |$info:ident, $output:ident| $body:block) => { ... };
}

Generates a panic-safe unsafe extern "C" table function scan callback.

The macro emits a function with signature:

unsafe extern "C" fn $name(
    info: duckdb_function_info,
    output: duckdb_data_chunk,
)

The body is wrapped in std::panic::catch_unwind. If the closure panics, the output chunk size is set to 0 (signaling end of stream) to prevent undefined behaviour from unwinding across the FFI boundary.

Parameters

• $name — the name of the generated function
• $body — a closure with signature |info: duckdb_function_info, output: duckdb_data_chunk|

Example

quack_rs::table_scan_callback!(my_scan, |info, output| {
    let chunk = unsafe { quack_rs::data_chunk::DataChunk::from_raw(output) };
    let mut writer = unsafe { chunk.writer(0) };
    unsafe { writer.write_i64(0, 42) };
    unsafe { chunk.set_size(1) };
});