Is anyone using duckdb with Nim?

[sdmcallister]

    var val = duckdb_value_varchar(addr(res), col.csize_t, row.csize_t)
    echo val
    free(addr(val))
    
    
    Run

The code above (full example below) causes the program to echo a value and then 
`Error: execution of an external program failed`.

I'm not sure if additional context will help clarify the situation. Does `free` 
require me to manually alloc memory? If not how do I properly free the 
resources in this context? Apologies for the many continued questions.
    
    
    include duckdb_wrapper
    
    proc free(p: pointer) {.importc: "free", header: "<stdlib.h>".}
    
    proc main() =
      var db: duckdb_database
      var con: duckdb_connection
      
      if (duckdb_open("test.db", db.addr) == DuckDBError):
        echo "Error"
      if (duckdb_connect(db, con.addr) == DuckDBError):
        echo "Error"
      
      if duckdb_query(con, "CREATE TABLE IF NOT EXISTS integers(i INTEGER, j 
INTEGER);", nil) == DuckDBError:
        echo "Error"
      if duckdb_query(con, "INSERT INTO integers VALUES (3, 4), (5, 6), (7, 
NULL);", nil) == DuckDBError:
        echo "Error"
      
      var res: duckdb_result
      if duckdb_query(con, "SELECT * FROM integers", addr(res)) == DuckDBError:
        echo "Error"
      
      # for row in 0..<3:
      #   for col in 0..<2:
      #     var val = duckdb_value_varchar(addr(res), col.csize_t, row.csize_t)
      #     echo val
     #  prints values as expected.
      
      var val = duckdb_value_varchar(addr(res), 0.idx_t, 0.idx_t)
      echo val
      free(addr(val)) # exits with error
      
      duckdb_destroy_result(addr(res))
      duckdb_disconnect(addr(con))
      duckdb_close(addr(db))
    
    main()
    
    
    Run