How do I use unity builds and their trade-offs with MSVC for C++?

Unity builds, or "Jumbo builds," are a technique in C++ development that allows multiple source files to be compiled into a single translation unit. This approach can lead to faster compile times and easier dependency management in large projects. However, there are trade-offs associated with using unity builds, especially when working with MSVC (Microsoft Visual C++). In this article, we will explore how to implement unity builds in MSVC, the advantages they offer, and the potential pitfalls you should be aware of.

// Example of a unity build implementation in MSVC

// main.cpp
#include "header1.h"
#include "header2.h"
#include "header3.h"

int main() {
    // Your main application logic
    return 0;
}

// header1.h
void function1();

// header2.h
void function2();

// header3.h
void function3();

// unity.cpp (all headers included - this file will be compiled as a single translation unit)
#include "main.cpp"
#include "header1.cpp"
#include "header2.cpp"
#include "header3.cpp"