OpenXLSX is a C++ library for reading, writing, creating and modifying Microsoft Excel® files, with the .xlsx format.

Many programming languages have the ability to modify Excel files, either natively or in the form of open source libraries. This includes Python, Java and C#. For C++, however, things are more scattered. While there are some libraries, they are generally less mature and have a smaller feature set than for other languages.

Because there are no open source library that fully fitted my needs, I decided to develop the OpenXLSX library.

Here is a summary of the main C++ libraries for Excel files that I'm aware of:

The libxls library (https://sourceforge.net/projects/libxls/) is a C library for reading files in the legacy Excel file format, .xls. It cannot be used for writing or modifying Excel files.

The xlslib library (https://sourceforge.net/projects/xlslib/) is a C/C++ library for creating files in the legacy Excel file format, .xls. It cannot be used for reading or modifying Excel files.

The libxlsxwriter library (https://libxlsxwriter.github.io) is a C library for creating .xlsx files. It cannot be used for reading or modifying Excel files.

The LibXL library (http://www.libxl.com) can read, write, create and modify Excel files, in both the .xls and .xlsx formats. It is the most feature complete library available and has interfaces for C, C++, C# and Delphi. It is only available for purchase, however.

Of the open source libraries, the QtXlsx library (https://github.com/dbzhang800/QtXlsxWriter) is the most feature complete. It is, however, based on the Qt framework. While I'm a big fan of Qt for application programming purposes, I don't believe it is the best option for lower-level libraries.

Recently, I found the XLNT library on GitHub (https://github.com/tfussell/xlnt). It was not available when I began developing OpenXLSX. To be honest, if it had, I wouldn't have begun OpenXLSX. It has a larger feature set and probably has fewer bugs. However, I decided to continue developing OpenXLSX, because I believe that in a few areas it is better than XLNT. Primarily, OpenXLSX is better able to handle very large spreadsheets.

The ambition is that OpenXLSX should be able to read, write, create and modify Excel files (data as well as formatting), and do so with as few dependencies as possible. Currently, OpenXLSX depends on the following 3rd party libraries (all included in the repository):

• PugiXML
• LibZip
• LibZip++

OpenXLSX is still work i progress. The following is a list of features which have been implemented and should be working properly:

• Create/open/save files
• Read/write/modify cell contents
• Copy cells and cell ranges
• Copy worksheets

Features related to formatting, plots and figures have not yet been implemented

It should be noted, that creating const XLDocument objects, is currently not working!

OpenXLSX can be built and run on the following platforms/compilers:

• Linux (GCC)
• MacOS (GCC/LLVM/Xcode)
• Windows (MinGW)

OpenXLSX can be compiled on Windows using MSVC, but there is an issue with the CMake script, which prevents MSVC finding the libraries. Building on Windows using MSYS has not been tested. Building using the Intel compiler has not been tested.

All string manipulations and usage in OpenXLSX uses the C++ std::string, which uses UTF-8 encoding. Also, Excel uses UTF-8 encoding internally (actually, it might be possible to use other encodings, but I'm not sure about that).

For the above reason, if you work with other text encodings, you have to convert to/from UTF-8 yourself. There are a number of options (e.g. std::codecvt or Boost.Locale). I will also suggest that you see James McNellis' presentation at CppCon 2014: https://youtu.be/n0GK-9f4dl8

#include <iostream>
#include <OpenXLSX/OpenXLSX.h>

using namespace std;
using namespace OpenXLSX;

int main() {

  XLDocument doc;
  doc.CreateDocument("MyTest.xlsx");
  auto wks = doc.Workbook()->Worksheet("Sheet1");

  *wks->Cell("A1")->Value() = 3.14159;
  *wks->Cell("B1")->Value() = 42;
  *wks->Cell("C1")->Value() = "Hello OpenXLSX!";
  *wks->Cell("D1")->Value() = true;

  auto A1 = wks->Cell("A1")->Value()->Get<double>();
  auto B1 = wks->Cell("B1")->Value()->Get<int>();
  auto C1 = wks->Cell("C1")->Value()->Get<std::string>();
  auto D1 = wks->Cell("D1")->Value()->Get<bool>();

  cout << "Cell A1: " << A1 << endl;
  cout << "Cell B1: " << B1 << endl;
  cout << "Cell C1: " << C1 << endl;
  cout << "Cell D1: " << D1 << endl;

  doc.SaveDocument();

return 0;
}