How to customize code completion for C++ in QtCreator?

[Dmitriy Blahodatnyi]

I had tried to customize QtCreator in such way that it could propose functions, variables and other benefits after typing a point before I came here. I think it simply does not see headers such as iostream, sstream, but code completion for QHeaders does work. How to fix that problem?

[J.Hilk]

Do you know that there is such a function in QtCreator already? the usuall Key-Combination is ctrl + spacebar?

For other classes that you include, you usually have to add the namespace beforehand to access/show the functions. NameSpace:: ctrl + spacebar or use using namespace NameSpace if you don't want to type them everytime you use them.