How to read/write Excel in C++

It is not difficult to write/read Excel data in VB/VBA, the development language included with most Microsoft Office products. It's another story if wring such an application using C++.
It seems the most popular method is to use OLE (Object Linking and Embedding) interface. The advantage is that you can use most Excel functions such as formula, format. The disadvantage is obvious, the application relies on Windows.
A class to be used in environments other than Windows would be welcomed by many developers. BasicExcel is such an open-source project. However, as the name indicates, its function is BASIC. You cannot expect too much on complicated applications.

References:
1. Comparison of methods of reading/writing EXCEL in C++ (chinese)
2. How to automate Excel from C++ without using MFC or #import
3. BasicExcel-A Class to Read and Write to Microsoft Excel