Overcoming the ‘CMake Must Be Installed to Build Dlib’ Error- A Comprehensive Guide

Error: cmake must be installed to build dlib

Building software packages can sometimes be a challenging task, especially when you encounter unexpected errors during the installation process. One such error that many users come across while trying to build the dlib library is the message “error: cmake must be installed to build dlib.” This article aims to provide a comprehensive guide on understanding this error, its causes, and the steps to resolve it successfully.

The dlib library is a modern C++ toolkit containing machine learning algorithms and tools for creating complex software in C++ to solve real-world problems. It is widely used in various fields, including computer vision, robotics, and machine learning. However, to build dlib from source, you need to have a proper setup, which includes installing the necessary dependencies and tools.

The error message “error: cmake must be installed to build dlib” suggests that the CMake build system is missing from your system. CMake is an open-source, cross-platform build system that generates native build files that can be used to build projects. It is essential for building dlib, as it automates the process of compiling and linking the library’s source code.

There are several reasons why you might encounter this error:

1. Missing CMake: The most common reason for this error is that CMake is not installed on your system. To resolve this, you need to install CMake.

2. Incorrect CMake Version: Even if you have CMake installed, it might be an outdated version that is not compatible with the dlib version you are trying to build. Ensure that you have the correct version of CMake installed.

3. CMake Not Recognized: Sometimes, CMake might be installed, but your system does not recognize it. This can happen if the PATH environment variable does not include the directory where CMake is installed.

To resolve the “error: cmake must be installed to build dlib” error, follow these steps:

1. Install CMake: If you do not have CMake installed, download and install it from the official CMake website ( Choose the appropriate version for your operating system and follow the installation instructions.

2. Check CMake Version: After installing CMake, verify the version by running `cmake –version` in your terminal or command prompt. Ensure that the version is compatible with the dlib version you are trying to build.

3. Update PATH Environment Variable: If CMake is installed but not recognized, update your PATH environment variable to include the directory where CMake is installed. This step varies depending on your operating system. For Windows, you can add the path to the CMake bin directory to the system variables. For Linux and macOS, you can add the path to your `.bashrc` or `.zshrc` file.

4. Configure and Build dlib: Once you have CMake installed and updated, navigate to the dlib source directory and run the following commands to configure and build the library:

“`
mkdir build
cd build
cmake ..
make
“`

These commands create a build directory, configure the project using CMake, and compile the library.

By following these steps, you should be able to resolve the “error: cmake must be installed to build dlib” error and successfully build the dlib library on your system.