On machines with NVIDIA video cards, the C++ API Help default text size may display too small to read.
The default Dots Per Inch (DPI) is set too small.
To check the current DPI setting, run:
% xdpyinfo | grep "resolution"
resolution: 69x69 dots per inch
The above output is an example of a low DPI setting.
See the link 'LinuxQuestions.org' in the Related Information section below for a forum string on 'How to Stop DPI from changing on resolution change'.
For additional information about using the DPI to determine how large (in pixels) to draw an object on the display service, click NVIDIA Accelerated Linux Driver Set README and Installation Guide. In your browser menu click Edit > Find (or type CTRL+F). In the Find field, type 'Appendix Y. Dots Per Inch'.