下文什么意思，好象有歧义

A driver should not be linked with the standard C runtime library. Besides being wasteful of memory space (each of 20 drivers should not include the same C runtime library support), some library routines are stateful or hold context information that is not thread-safe or driver-safe.
〈摘自 The Windows 2000 Device Driver Book, A Guide for Programmers, Second Edition>
前面说不能用，后面又说每20个不能包括相同的动态库，什么意思？是不是我理解错了？