How to Generate Excel Files in C++ Using xlsLib Generating spreadsheet reports directly from a C++ application is a common business requirement. While exporting data to a CSV file is easy, it lacks formatting, fonts, colors, and multi-worksheet capabilities.
To create native Excel spreadsheets without a dependency on Microsoft Office or heavy automation frameworks, the xlsLib open-source library is an excellent, lightweight choice. It is a fast, portable C/C++ library designed to construct Excel files in the BIFF8 (Excel 97-2003 .XLS) format from scratch. Key Features of xlsLib
Zero Dependencies: Does not require Microsoft Excel to be installed on the host machine.
Multi-Platform: Works smoothly across Windows, Linux, and macOS environments.
Rich Formatting: Supports cell fonts, custom colors, text alignment, borders, and number formatting.
Multiple Worksheets: Allows you to spawn and organize multiple sheets within a single workbook file. Step 1: Setting Up xlsLib in Your Project
Before writing code, you need to compile and link the library to your environment.
Download the Source: Clone the repository from the xlsLib GitHub page. Build the Library:
On UNIX-based systems (Linux/macOS), run the standard autotools pipeline: ./configure, make, and make install.
On Windows, use the provided Visual Studio solution file (.sln) in the project directory to compile xlslib.lib.
Include Headers: Ensure your C++ project compiler path points to the xlslib/ header directory. Step 2: Understanding the Core Architecture
The C++ object hierarchy inside xlsLib mirrors the natural structure of a spreadsheet:
workbook: The main container representing the entire Excel file.
worksheet: Individual tabs inside the file where data actually lives.
cell: The grid units referenced by 0-indexed row and column coordinates.
xf_t: The format descriptor object responsible for fonts, borders, and styles. Step 3: Complete C++ Implementation Example
Below is a production-ready C++ code example showing how to initialize a workbook, apply custom styling to header blocks, inject text or numeric values, and save the binary document. Use code with caution. Step 4: Compiling Your Code
When building your program, link the compiled library binary to your executable. For GCC or Clang setups via terminal: g++ -std=c++11 main.cpp -o excel_gen -lxls -lxlslib Use code with caution.
(Note: Ensure your library search paths -L and include paths -I are provided if the library is not installed globally). Best Practices & Limitations
0-Based Indexing: Both rows and columns utilize 0-indexed values in xlsLib. For instance, cell A1 corresponds to row 0, column 0.
Format Cache Limits: Create your font (font_t) and formatting (xf_t) objects through the workbook instance before the main loops. Re-creating styles inside high-iteration loops will overflow Excel’s internal formatting index limits.
File Extensions: Because xlsLib formats files using the classic BIFF8 specification, always save files using the .xls extension rather than the modern XML-zipped .xlsx format. Modern Excel applications will open these seamlessly via legacy compatibility mode.
If you would like to expand this implementation, please let me know:
Should we integrate mathematical Excel formulas into the rows?
Do you need help with cell merging or setting specific column widths?