Building Software#

Build systems automate the process of compiling source code into executables or libraries.
They manage dependencies, compiler flags, and installation steps, making builds portable and repeatable.

General Flow#

Source Code → Configuration → Build Files → Compilation Installation

Source Code#

  • Contains .c, .cpp, .h, and related source files.

  • Includes metadata files that describe how to build (e.g., CMakeLists.txt, configure.ac, Makefile.am).

Configuration#

  • Detects system settings, compilers, and libraries.

  • Generates platform-specific build files (like Makefiles or Visual Studio projects).

Build#

  • Uses generated build files to compile and link the code.

Installation#

  • Copies binaries, headers, and other files to system directories.

Example: CMake#

Configuration → Build → Install

# create build dir
mkdir build; cd build

# Step 1: Configure (generate build system files)
cmake .. -DCMAKE_INSTALL_PREFIX=/path/to/prefix

# (Optional) Use ccmake for more transparency
ccmake ..

# Step 2: Build
make -j

# Step 3: Install
make install

Note

If you’re unsure what variables you can tweak in a cmake project, you can launch a terminal user interface by using ccmake in place of cmake

Files involved:

  • CMakeLists.txt: Describes targets, dependencies, and options.

  • build/: Directory containing generated Makefiles or project files.

Typical flow:

CMakeLists.txt → CMake generates Makefiles → make builds → make install

Example: GNU Autotools#

Bootstrap → Configure → Build → Install

# Step 1: Generate configuration scripts (for maintainers)
autoreconf -i

# Step 2: Configure (generate Makefiles)
./configure --prefix=/path/to/prefix

# Step 3: Build
make -j$(nproc)

# Step 4: Install
make install

Files involved:

  • configure.ac: Defines project metadata and system checks.

  • Makefile.am: High-level Makefile template.

  • Makefile.in and configure: Generated intermediate files.

Typical flow:

configure.ac + Makefile.am → autoreconf → configure → Makefiles → make → make install

Comparison Summary#

Step

CMake

Autotools

Input file(s)

CMakeLists.txt

configure.ac, Makefile.am

Configuration tool

cmake

autoreconf, configure

Output files

Makefiles or project files

Makefile

Build command

cmake --build / make

make

Install command

cmake --install / make install

make install

Portability focus

Cross-platform (Windows/Linux/macOS)

Primarily Unix-like systems