http://www.chm-pdf.com/ebook/beginning-linux-programming-4th-cn.html
http://www.baidupcs.com/file/731a09b2e3332c4439a2f8fb0ca6c862?fid=2433647962-250528-1090855442&time=1362916712&sign=FDTA-DCb740ccc5511e5e8fedcff06b081203-k6%2B%2B500ahf79JYRw6RKb1HVwYF8%3D&expires=1h