How to open standard library headers?

[Munto]

Hello !
I'm pretty new to Codeblocks and C in general and I would like to open header files to see which functions are available in one click.

When I right click on #include <stdio.h> in the editor and select "Open #include file: 'stdio.h'", a popup opens and says "Not found: stdio.h".
So, is there a way to say to codeblocks where to find stdio.h in order to open it easily?

[oBFusCATed]

Do you have a compiler?
Which version do you use? Which OS?
Do you have a project?

It works for me for C++ projects.

[Munto]

Glad to read it!

I have only gcc as compiler, at least, it is what codeblocks suggests to me when I launch it.
gcc version 6.2.1 20160830 (GCC)

My running OS is archlinux and I have codeblocks 16.01
I found out that all C libraries were contained in the folder /usr/include

Edit:
After taking the time to read what was written in the popup when I launch codeblocks, I have the feeling that the IDE is not correctly configured.
I join a screenshot for more details.
I tried to navigate in settings and menus but all of that is a bit confusing and not really explicit for me.

Thank you for your help.