Struct FFI_ScalarFunction

Source

#[repr(C)]pub struct FFI_ScalarFunction {
    pub ctx: *const c_void,
    pub name: unsafe extern "C" fn(ctx: *const c_void) -> *const c_char,
    pub get_return_field: unsafe extern "C" fn(ctx: *const c_void, args: *const ArrowSchema, args_count: usize, ret: *mut ArrowSchema, errmsg: *mut *mut c_char) -> c_int,
    pub call: unsafe extern "C" fn(ctx: *const c_void, args: *const ArrowArray, args_schemas: *const ArrowSchema, args_count: usize, ret_array: *mut ArrowArray, ret_schema: *mut ArrowSchema, errmsg: *mut *mut c_char) -> c_int,
    pub fini: unsafe extern "C" fn(ctx: *mut c_void),
}

Expand description

Virtual function table for a scalar function.

The host calls methods through these function pointers. ctx is an opaque pointer owned by the module; the host never dereferences it directly.

Fields§

§ctx: *const c_void

Opaque module-side context pointer.

§name: unsafe extern "C" fn(ctx: *const c_void) -> *const c_char

Return the function name as a null-terminated UTF-8 string.

The returned pointer borrows from ctx and is valid until fini.

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get_return_field: unsafe extern "C" fn(ctx: *const c_void, args: *const ArrowSchema, args_count: usize, ret: *mut ArrowSchema, errmsg: *mut *mut c_char) -> c_int

Compute the output field given input fields.

args points to args_count Arrow field schemas (C Data Interface). On success, writes the result schema to *ret. On error, writes a null-terminated message to *errmsg (freed by FFI_Module::free_string).

Returns 0 on success, non-zero on error.

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call: unsafe extern "C" fn(ctx: *const c_void, args: *const ArrowArray, args_schemas: *const ArrowSchema, args_count: usize, ret_array: *mut ArrowArray, ret_schema: *mut ArrowSchema, errmsg: *mut *mut c_char) -> c_int