How to move executable after build?

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Summary

The VS Code CMake tools extension is a powerful tool for building and managing CMake projects within the Visual Studio Code environment. However, managing the build output and executable location can be confusing, especially for those new to CMake or VS Code. This article addresses the question of how to configure the extension to build projects in a build/ folder and then move the executable to and run it from a bin/ folder.

Root Cause

The root cause of the confusion lies in understanding how CMake generates build files and how the VS Code CMake tools extension interacts with these files. Key points include:

  • CMake generates build files in a specified directory.
  • The VS Code CMake tools extension uses these build files to compile the project.
  • By default, the executable is placed in the build directory specified by CMake.

Why This Happens in Real Systems

This situation occurs in real systems due to several reasons:

  • Separation of Concerns: Developers often want to separate build artifacts from source code for cleanliness and ease of management.
  • Deployment: Executables need to be in specific locations for deployment or execution purposes.
  • Reusability: Having a standardized way to move executables after build facilitates reusability across different projects and environments.

Real-World Impact

The impact of not properly managing build outputs and executables includes:

  • Cluttered Source Directory: Build artifacts can clutter the source directory, making it harder to manage and version control the project.
  • Inconsistent Deployment: Without a standardized way to move executables, deployment processes can become inconsistent and prone to errors.
  • Difficulty in Automation: Automating build and deployment processes becomes more challenging when the location of executables is not predictable.

Example or Code

# Specify the build directory
set(CMAKE_BINARY_DIR ${CMAKE_SOURCE_DIR}/build)

# Specify the executable output directory
set(EXECUTABLE_OUTPUT_PATH ${CMAKE_SOURCE_DIR}/bin)

# Example of adding an executable
add_executable(MyExecutable main.cpp)

# Move the executable to the bin directory after build
add_custom_command(
    TARGET MyExecutable
    POST_BUILD
    COMMAND ${CMAKE_COMMAND} -E copy $ ${EXECUTABLE_OUTPUT_PATH}
)

How Senior Engineers Fix It

Senior engineers fix this issue by:

  • Understanding CMake: They have a deep understanding of how CMake works and how to configure it to meet specific build and deployment needs.
  • Configuring CMakeLists.txt: They know how to write and configure CMakeLists.txt files to specify build directories, executable output paths, and custom commands for moving executables after build.
  • Utilizing VS Code Extensions: They are familiar with the capabilities and limitations of the VS Code CMake tools extension and know how to configure it to work seamlessly with their CMake setup.

Why Juniors Miss It

Juniors might miss this because:

  • Lack of Experience with CMake: They may not have extensive experience with CMake or building complex projects, leading to a lack of understanding of how to configure build outputs and executables.
  • Unfamiliarity with VS Code Extensions: They might not be fully familiar with the VS Code CMake tools extension or its configuration options, making it harder for them to set up the build and deployment process as desired.
  • Insufficient Documentation: Sometimes, the documentation for CMake or the VS Code extension might not clearly explain how to achieve specific build and deployment configurations, leading to confusion.

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