Function libsession_session_is_active 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn libsession_session_is_active(
    ctx: *mut LibsessionContext,
    session: *const LibsessionSession,
    ret_active: *mut bool,
) -> LibsessionStatus

Safety

ctx and session must be valid, and ret_active must point to writable storage.