How opencv 4.x API is different from previous version?

Question

I noted that opencv 4 is released and one difference is that API changed to be c++11 compliant.

What this really means?

How should I change my codes to be compat

Answer 1

According to OpenCV 4.0.0, you don't have to make any significant modifications (most likely any at all) to your source codes, unless you are using some C API which has been removed.

As already stated

OpenCV is now C++11 library and requires C++11-compliant compiler

To use c++11, clang version 3.3 and higher is required with flag -std=c++11. Same for g++ 4.3 and higher.

It allows them to use std::string instead of cv::String, and other c++11 features. But don't worry, cv::String will still work, but is now allias for std::string. Similliar for smart pointers, etc.