Get data from any framework / project without changing too much code

i did not find anything like this or maybe this has a specific name, which i did not figure out yet. So here is my question.

I have a framework / project which computes and generates data during its process. During this process i like to grab some data into a class which will be later collected and used by my own written project. The data type could be anything of int, float, vectors and so on.

My idea was to use something like a template logger class where you only include the header file, which gives you access to several functions which will save the data for me. For this i found the class / pattern called "Singleton".

I'm now wondering if this is the best solution for this problem. Maybe you have some ideas / pattern / links / code snipptes which shows me how to do this easily without changing to much code in the framework where i want so get the data from.

Thank you

c0op