Getting a windows text in C++?

Hello so recently I have been programming in C++. Please note I compile using -std=c++11 being checked, and use Code::Blocks with MingW compiler because some of the program requires it. My question is simple: can anyone provide me with a function to get the text of an input bar? I ask this because I cant seem to find working implementations of WM_GETTEXT or GetWindowText.

Thanks!