Streamlining CMake Projects: Grouping Generated Files for Easier Management

What it is

• It allows you to specify a custom group name to categorize these files, making project navigation and management easier within IDEs or build tools that support CMake project structure.
• AUTOGEN_SOURCE_GROUP is a global property in CMake that controls how automatically generated source files are organized within your project's build tree.

How it works

• Setting the AUTOGEN_SOURCE_GROUP property provides a way to group these automatically generated files under a specific heading in your IDE or build tool.
• By default, CMake generates source files (like those created by tools like configure_file or custom commands) in the same directory where the generating CMakeLists.txt file resides.

Setting the property

• You can set the AUTOGEN_SOURCE_GROUP property using the cmake_minimum_required command at the beginning of your main CMakeLists.txt file:

cmake_minimum_required(VERSION 3.10)  # Minimum CMake version required (3.10 or later)
project(MyProject)

set(AUTOGEN_SOURCE_GROUP "CustomGeneratedSources")  # Set the group name

Benefits

• Easier navigation in IDEs: Many IDEs that integrate with CMake projects display the source groups, allowing you to quickly locate and browse through generated files.
• Improved project organization: Grouping automatically generated files helps keep your project structure cleaner and more manageable, especially if you have a significant number of these files.

Example

cmake_minimum_required(VERSION 3.10)
project(MyProject)

set(AUTOGEN_SOURCE_GROUP "GeneratedFiles")

configure_file(config.h.in config.h OUTPUT_FILE ${CMAKE_CURRENT_BINARY_DIR})

# Generated config.h will now be placed under the "GeneratedFiles" group in your IDE

• Consult your IDE's documentation to understand how it specifically handles CMake project structure and source groups.
• This property affects all automatically generated files within your project, unless you override it for specific files using the SOURCE_GROUP property on individual files.
• The specific name you choose for the group is up to you; it's a convention to use descriptive names for clarity.

---

Grouping Qt-generated files (AUTOMOC and AUTORCC)

cmake_minimum_required(VERSION 3.9)  # Minimum CMake version required (3.9 or later)
project(MyQtProject)

find_package(Qt REQUIRED)  # Find Qt libraries

set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
set(AUTOGEN_SOURCE_GROUP "QtGenerated")

set(UI_FILES mainwindow.ui)
set(MOC_HEADERS moc_mainwindow.cpp)  # Generated by automoc

qt_ui_generate(UI_FILES OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
qt_moc_sources(MOC_HEADERS)

add_executable(MyQtApp mainwindow.cpp ${MOC_HEADERS})
target_link_libraries(MyQtApp Qt5Widgets)

# mainwindow.cpp and moc_mainwindow.cpp will be grouped under "QtGenerated"

Grouping custom-generated files using configure_file

cmake_minimum_required(VERSION 3.10)
project(MyProject)

set(AUTOGEN_SOURCE_GROUP "CustomFiles")

configure_file(data.txt.in data.txt OUTPUT_FILE ${CMAKE_CURRENT_BINARY_DIR})
configure_file(config.h.in config.h OUTPUT_FILE ${CMAKE_CURRENT_BINARY_DIR}/include)

# data.txt and config.h (placed in the include directory) will be grouped under "CustomFiles"

cmake_minimum_required(VERSION 3.10)
project(MyProject)

set(AUTOGEN_SOURCE_GROUP "Generated")

configure_file(data.txt.in data.txt OUTPUT_FILE ${CMAKE_CURRENT_BINARY_DIR})
configure_file(config.h.in config.h OUTPUT_FILE ${CMAKE_CURRENT_BINARY_DIR})

source_group(FILES data.txt PROPERTIES SOURCE_GROUP "MyDataFiles")  # Override for data.txt

# config.h will be in "Generated", data.txt will be in "MyDataFiles"

---

Manual Directory Structure

• You can create dedicated directories within your project to organize the generated files. This approach offers more granular control over the structure, but can require additional maintenance to keep things organized.

cmake_minimum_required(VERSION 3.10)
project(MyProject)

configure_file(data.txt.in data.txt OUTPUT_FILE ${CMAKE_CURRENT_BINARY_DIR}/generated/data)
configure_file(config.h.in config.h OUTPUT_FILE ${CMAKE_CURRENT_BINARY_DIR}/generated/include)

# Generated files are placed in subdirectories within "generated"

SOURCE_GROUP for Individual Files

• You can use the SOURCE_GROUP property directly on individual source files using set_source_files_properties. This provides flexibility for fine-grained organization, but can lead to more verbose CMakeLists.txt files.

cmake_minimum_required(VERSION 3.10)
project(MyProject)

configure_file(data.txt.in data.txt OUTPUT_FILE ${CMAKE_CURRENT_BINARY_DIR})
configure_file(config.h.in config.h OUTPUT_FILE ${CMAKE_CURRENT_BINARY_DIR})

set_source_files_properties(data.txt PROPERTIES SOURCE_GROUP "MyDataFiles")
set_source_files_properties(config.h PROPERTIES SOURCE_GROUP "GeneratedHeaders")

# Each file has its specific source group

• For large projects with many generated files, consider AUTOGEN_SOURCE_GROUP combined with subdirectories within the chosen group for better hierarchy.
• If you need very specific custom organization or a more manual approach, you can consider using manual directory structures or individual SOURCE_GROUP assignments.
• For most projects, AUTOGEN_SOURCE_GROUP is the recommended approach due to its simplicity and adherence to CMake conventions.