YouTip

This tutorial demonstrates how to use CMake to manage a moderately complex project, covering the entire process from project creation to compilation and execution, including practical applications from basic configurations to advanced features.

\n\n

The practical exercises include the following:

\n

\n
1. Create CMakeLists.txt files: Define projects, libraries, executables, and tests.
\n
2. Write source code and tests: Write code and test files.
\n
3. Create a build directory: Keep the source directory clean.
\n
4. Configure the project: Generate build system files.
\n
5. Compile the project: Generate target files.
\n
6. Run the executable: Execute the program.
\n
7. Run tests: Verify functional correctness.
\n
8. Use custom commands and targets: Perform additional operations.
\n
9. Cross-platform and cross-compilation: Support different platforms and architectures.
\n

\n\n

Building a Simple C++ Project

\n

Suppose we have a project containing a main program and a library, with two different functional modules in the library.

\n

The project structure is as follows:

\n

MyProject/\n├── CMakeLists.txt\n├── src/\n│   ├── main.cpp\n│   ├── lib/\n│   │   ├── module1.cpp\n│   │   ├── module2.cpp\n│   ├── include/\n│   └── mylib.h\n└── tests/\n    ├── test_main.cpp\n    └── CMakeLists.txt

\n\n

---

\n\n

1. Create CMakeLists.txt Files

\n\n

1.1 Root Directory CMakeLists.txt File

\n

Create a CMakeLists.txt file in the root directory of MyProject:

\n

Example

\n

cmake_minimum_required(VERSION 3.10)# Specify the minimum CMake version\n\n project(MyProject VERSION 1.0)# Define the project name and version\n\n# Set C standard++ Standard\n\n set(CMAKE_CXX_STANDARD 11)\n\n set(CMAKE_CXX_STANDARD_REQUIRED ON)\n\n# Include header file paths\n\n include_directories(${PROJECT_SOURCE_DIR}/src/include)\n\n# Add subdirectories\n\n add_subdirectory(src)\n\n add_subdirectory(tests)

\n\n

1.2 src Directory CMakeLists.txt File

\n

Create a CMakeLists.txt file in the src directory:

\n

Example

\n

# Create a library target\n\n add_library(MyLib STATIC\n\n lib/module1.cpp\n\n lib/module2.cpp\n\n )\n\n# Specify the library's header files\n\n target_include_directories(MyLib PUBLIC ${CMAKE_SOURCE_DIR}/src/include)\n\n# Create an executable target\n\n add_executable(MyExecutable main.cpp)\n\n# Link the library to the executable\n\n target_link_libraries(MyExecutable PRIVATE MyLib)

\n\n

1.3 tests Directory CMakeLists.txt File

\n

Create a CMakeLists.txt file in the tests directory:

\n

Example

\n

# Find GTest package\n\n find_package(GTest REQUIRED)\n\n include_directories(${GTEST_INCLUDE_DIRS})\n\n# Create a test target\n\n add_executable(TestMyLib test_main.cpp)\n\n# Link library and GTest to the test target\n\n target_link_libraries(TestMyLib PRIVATE MyLib ${GTEST_LIBRARIES})

\n\n

---

\n\n

2. Write Source Code and Tests

\n

Below is the code for each file:

\n\n

2.1 src/main.cpp File Code

\n

Example

\n

#include \n\n#include "mylib.h"\n\nint main(){\n\n std::cout<<"Hello, CMake!"<< std::endl;\n\nreturn 0;\n\n}

\n\n

2.2 src/lib/module1.cpp File Code

\n

Example

\n

#include "mylib.h"\n\n// Implementation of module1

\n\n

2.3 src/lib/module2.cpp File Code

\n

Example

\n

#include "mylib.h"\n\n// Implementation of module2

\n\n

2.4 src/include/mylib.h File Code

\n

Example

\n

#ifndef MYLIB_H\n\n#define MYLIB_H\n\n// Declarations of module functions\n\n#endif // MYLIB_H

\n\n

2.5 tests/test_main.cpp File Code

\n

Example

\n

#include \n\n// Test cases for MyLib\n\n TEST(MyLibTest, BasicTest){\n\n EXPECT_EQ(1, 1);\n\n}

\n\n

---

\n\n

3. Create Build Directory

\n

Create a build directory in the project root:

\n

mkdir build cd build

\n\n

---

\n\n

4. Configure Project

\n

Run CMake in the build directory to configure the project:

\n

cmake ..

\n\n

---

\n\n

5. Compile Project

\n

Compile using the generated build system files, assuming a Makefile was generated:

\n

make

\n\n

---

\n\n

6. Run Executable

\n

After compilation, you can run the generated executable:

\n

./MyExecutable

\n\n

---

\n\n

7. Run Tests

\n

Run tests using the generated test target:

\n

./TestMyLib

\n\n

---

\n\n

8. Use Custom Commands and Targets

\n\n

8.1 Custom Command

\n

Add a custom command in the src/CMakeLists.txt file:

\n

add_custom_command( TARGET MyExecutable POST_BUILD COMMAND ${CMAKE_COMMAND} -E echo "Build complete!")

\n\n

8.2 Custom Target

\n

Add a custom target in the src/CMakeLists.txt file:

\n

add_custom_target(run COMMAND ${CMAKE_BINARY_DIR}/MyExecutable DEPENDS MyExecutable)

\n

Run the custom target:

\n

make run

\n\n

---

\n\n

9. Cross-Platform and Cross-Compilation

\n\n

9.1 Specify Platform

\n

If you need to specify a platform for building, you can specify it when running CMake:

\n

cmake -DCMAKE_SYSTEM_NAME=Linux ..

\n\n

9.2 Using a Toolchain File

\n

Create a toolchain file named toolchain.cmake:

\n

set(CMAKE_SYSTEM_NAME Linux)set(CMAKE_SYSTEM_PROCESSOR arm)

\n

Build using the toolchain file:

\n

cmake -DCMAKE_TOOLCHAIN_FILE=toolchain.cmake ..