如何识别二维码？

二维码生成库

1.qrcode
https://github.com/rsky/qrcode
2.libqrencode
https://github.com/fukuchi/libqrencode

二维码识别库

1.zxing c++版
https://github.com/glassechidna/zxing-cpp
2.qzxing Qt版
https://github.com/ftylitak/qzxing
3.ZBar
http://zbar.sourceforge.net/