How The Build Works

The following describes the components that participate in the process of building a typical compiled software project (C/C++ in this case). One does not need to understand any of the following description to be able to build Xmera. However, the interested reader may find it provides a mental model of what happens in the building of this (or many millions of other) projects.

1. Header and Source Files (Your Input Code)

These are the starting point — your .cpp and .h files. They contain the logic, declarations, and definitions that make up your program.

2. CMake (The Build Configuration Tool)

CMake is like the project manager. You give it a high-level description of your project via CMakeLists.txt files:

• Which source files exist

• What targets (executables, libraries) to build

• What compiler flags or definitions to use

• What dependencies to link

CMake does not build anything itself. Instead, it generates files for the actual build system you’ll use.

3. Generators (The Output Format Specifier)

CMake uses a generator to determine what kind of build system files to produce.

Examples of generators:

• Unix Makefiles → Generates Makefiles for use with make

• Ninja → Generates build.ninja files for ninja

• Visual Studio → Generates .sln and .vcxproj for MSVC IDE

You pick the generator depending on your platform or preference.

4. Build System (The Build Executor)

This is the tool that actually performs the build steps by following the instructions CMake generated:

• Make reads Makefile

• Ninja reads build.ninja

• Visual Studio/MSBuild reads solution/project files

It calls the compiler, tracks dependencies, and decides what needs rebuilding.

5. Compiler (The Code Translator)

The compiler (e.g., g++, clang++, cl.exe) compiles individual .cpp files into .o/.obj object files.

The compiler is invoked by the build system — not directly by CMake (except for test detection and introspection).

6. Linker (The Final Assembler)

After all source files are compiled, the linker combines them:

• It links object files and libraries into a single executable or shared/static library.

• It resolves symbols and dependencies.

The linker is usually invoked as part of the compiler toolchain (g++ or clang++ often handle linking too).

Each component hands off its results to the next — forming a pipeline from code to binary.

Summary

Build Component Responsibilities

Component	Responsibility
Header/Source	Contains code logic and declarations
CMake	Describes project structure/configuration
Generator	Chooses format for build system files
Build System	Executes compilation and linking steps
Compiler	Translates source code into machine code (object files)
Linker	Combines object files into final output