ensure-sqlite3-terribly.rs

#[cfg(feature = "sqlcipher")]
#[link(name = "sqlcipher")]
extern "C" {
    fn sqlite3_key(
        db: *mut ::std::os::raw::c_void,
        p_key: *const ::std::os::raw::c_void,
        n_key: ::std::os::raw::c_int
    ) -> ::std::os::raw::c_int;
}
#[cfg(feature = "sqlcipher")]
#[inline(never)]
fn hacky_ensure_sqlcipher_exists() {
    use std::ptr;
    // Use the address of sqlite3_key here, and write it into a volatile "buffer".
    // This is a crude way of forcing a linking failure if sqlite3_key is not
    // available, without requiring us actually call sqlite3_key.
    let p = (&sqlite3_key as *const _) as usize;
    let mut dest: usize = 0;
    unsafe {
        ptr::write_volatile(&mut dest as *mut usize, p);
    }
}