Type Definition udf_sys::Udf_func_string

pub type Udf_func_string = Option<unsafe extern "C" fn(initid: *mut UDF_INIT, args: *const UDF_ARGS, result: *mut c_char, length: *mut c_ulong, is_null: *mut c_uchar, error: *mut c_uchar) -> *mut c_char>;

Function signature of an xxx(...) function returning a SQL string