I have seen a lot of C/C++ Libraries and Gui Toolkits. Among them there are some like GTK+ , Qt , Swing etc. which claim to be platform-independent. While some , like WxWidgets, SWT etc. which claim to be cross-platform. At first I thought it to be just a change in wording, but the terms have been used with such consistency that I have started to wonder. What is the difference?
Cross-platform only implies that you support multiple platforms. It usually means Linux, Mac, and Windows. Platform-independent implies that you support any platform that your language supports- i.e., you depend on no behaviour that is not specified in the language specification. However that's just my personal opinion and most uses just take both of them to mean "multiple platforms", usually "Windows and ...".