做个笔记也方便别人搜索
转自 http://blog.csdn.net/woainiliuwei007/article/details/51993495
最近更新了cocoapods之后出现了Undefined symbols for architecture arm64:
"OBJC_CLASS$_FBSession", referenced from: someFile
ld: symbol(s) not found for architecture arm64
找了半天原因没有找到,在网上搜索也无果,最后发现是由于之前的三方类库编译文件已存在,导致更新的类库无法编译,才造成arm64这个错误出现,只需要在libPods-xxxx.a点Show in Finder,将Products目录下文件全部清空,重新编译就好了