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Michael Waite edited this page Mar 13, 2026 · 4 revisions

tbXLLerator Wiki

Welcome to the tbXLLerator wiki — the companion documentation for the tbXLLerator framework, a twinBASIC XLL framework for building high-performance Excel User-Defined Functions.


What is tbXLLerator?

tbXLLerator is a framework that lets you build Excel XLL add-ins entirely in twinBASIC, without requiring C or C++. It wraps Jon Johnson's ExcelSDK and provides a structured layer for argument binding, type coercion, memory management, UDF registration, and Excel callback mechanics.

The result is that you can focus on your modeling logic while the framework handles the low-level plumbing that makes XLL development notoriously difficult.


Why XLL?

Excel supports several add-in technologies. Here's where XLL fits in:

Technology Language Thread-Safe Calc Performance Function Wizard
XLL C/C++, twinBASIC Yes Fastest Full support
COM Add-in VB.NET, C#, twinBASIC No Moderate Limited
VBA VBA No Slowest No
Office.js JavaScript N/A Varies Partial

XLL add-ins are native DLLs that plug directly into Excel's calculation engine. The key advantages are multithreaded recalculation (Excel can call your UDF concurrently across CPU cores) and full Function Wizard integration (descriptions, argument help, help topics).


Wiki Structure

This wiki is organized into four sections:

Getting Started covers installation, prerequisites, and a minimal working example to get you up and running.

Core Concepts explains the foundational ideas behind XLL development — how memory works, how arguments flow between Excel and your code, how registration tells Excel about your functions, and how thread safety is achieved.

How-To Guides are task-oriented pages that walk through specific patterns: arrays, error handling, optional arguments, delegating to Excel built-ins, cell references, and performance tuning.

Reference provides lookup tables for enums, type codes, and architectural details.


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