mirror of
https://github.com/ttroy50/cmake-examples.git
synced 2025-12-18 12:14:36 +03:00
149 lines
4.2 KiB
Plaintext
149 lines
4.2 KiB
Plaintext
= Basic Sub-Project
|
|
:toc:
|
|
:toc-placement!:
|
|
|
|
toc::[]
|
|
|
|
# Introduction
|
|
|
|
This example shows how to setup a CMake project that includes sub-projects. The
|
|
top level CMakeLists.txt calls the CMakeLists.txt in the sub directories to
|
|
create the following:
|
|
|
|
* sublibrary1 - A static library
|
|
* sublibrary2 - A header only library
|
|
* subbinary - An executable
|
|
|
|
The files included in this example are:
|
|
|
|
```
|
|
$ tree
|
|
.
|
|
├── CMakeLists.txt
|
|
├── subbinary
|
|
│ ├── CMakeLists.txt
|
|
│ └── main.cpp
|
|
├── sublibrary1
|
|
│ ├── CMakeLists.txt
|
|
│ ├── inc
|
|
│ │ └── sublib1.h
|
|
│ └── src
|
|
│ └── sublib1.cpp
|
|
└── sublibrary2
|
|
├── CMakeLists.txt
|
|
└── inc
|
|
└── sublib2.h
|
|
```
|
|
|
|
* link:CMakeLists.txt[] - Top level CMakeLists.txt
|
|
* link:subbinary/CMakeLists.txt[] - to make the executable
|
|
* link:subbinary/main.cpp[] - source for the executable
|
|
* link:sublibrary1/CMakeLists.txt[] - to make a static library
|
|
* link:sublibrary1/inc/sublib1.h[]
|
|
* link:sublibrary1/src/sublib2.cpp[]
|
|
* link:sublibrary2/CMakeLists.txt[] - to setup header only library
|
|
* link:sublibrary2/inc/sublib2.h[]
|
|
|
|
# Concepts
|
|
|
|
## Adding a Sub-Directory
|
|
|
|
A CMakeLists.txt file can include and call sub-directories which include a CMakeLists.txt
|
|
files.
|
|
|
|
[source,cmake]
|
|
----
|
|
add_subdirectory(sublibrary1)
|
|
add_subdirectory(sublibrary2)
|
|
add_subdirectory(subbinary)
|
|
----
|
|
|
|
## Referencing Sub-Project Directories
|
|
|
|
When a project is created using the `project()` command, CMake will automatically
|
|
create a number of variables which can be used to reference details about the project.
|
|
These variables can then be used by other sub-projects or the main project. For exampe,
|
|
to include header files between projects.
|
|
|
|
[source,cmake]
|
|
----
|
|
include_directories(
|
|
${sublibrary1_SOURCE_DIR}/inc
|
|
${sublibrary2_SOURCE_DIR}/inc
|
|
)
|
|
----
|
|
|
|
The variables created by CMake include:
|
|
|
|
[cols=",",options="header",]
|
|
|=======================================================================
|
|
|Variable |Info
|
|
|PROJECT_NAME | The name of the project set by the current `project()`.
|
|
|
|
|CMAKE_PROJECT_NAME |the name of the first project set by the `project()`
|
|
command, i.e. the top level project.
|
|
|
|
|PROJECT_SOURCE_DIR |The source director of the current project.
|
|
|
|
|PROJECT_BINARY_DIR |The build directory for the current project.
|
|
|
|
|name_SOURCE_DIR | The source directory of the project called "name".
|
|
In this example the source directories created would be `sublibrary1_SOURCE_DIR`,
|
|
`sublibrary2_SOURCE_DIR`, and `subbinary_SOURCE_DIR`
|
|
|
|
|name_BINARY_DIR | The binary directory of the project called "name".
|
|
In this example the binary directories created would be `sublibrary1_BINARY_DIR`,
|
|
`sublibrary2_BINARY_DIR`, and `subbinary_BINARY_DIR`
|
|
|
|
|=======================================================================
|
|
|
|
|
|
## Referencing Libraries from Sub-Projects
|
|
|
|
If a sub-project creates a library, it can be referenced by other projects by
|
|
calling the name of the project in the `target_link_libraries()` command. This
|
|
means that you don't have to reference the full path of the new library and it
|
|
is added as a dependency.
|
|
|
|
[source,cmake]
|
|
----
|
|
target_link_libraries(subbinary
|
|
sublibrary1
|
|
)
|
|
----
|
|
|
|
# Building the example
|
|
|
|
[source,bash]
|
|
----
|
|
$ mkdir build
|
|
|
|
$ cd build/
|
|
|
|
$ cmake ..
|
|
-- The C compiler identification is GNU 4.8.4
|
|
-- The CXX compiler identification is GNU 4.8.4
|
|
-- Check for working C compiler: /usr/bin/cc
|
|
-- Check for working C compiler: /usr/bin/cc -- works
|
|
-- Detecting C compiler ABI info
|
|
-- Detecting C compiler ABI info - done
|
|
-- Check for working CXX compiler: /usr/bin/c++
|
|
-- Check for working CXX compiler: /usr/bin/c++ -- works
|
|
-- Detecting CXX compiler ABI info
|
|
-- Detecting CXX compiler ABI info - done
|
|
-- Configuring done
|
|
-- Generating done
|
|
-- Build files have been written to: /home/matrim/workspace/cmake-examples/02-sub-projects/A-basic/build
|
|
|
|
$ make
|
|
Scanning dependencies of target sublibrary1
|
|
[ 50%] Building CXX object sublibrary1/CMakeFiles/sublibrary1.dir/src/sublib1.cpp.o
|
|
Linking CXX static library libsublibrary1.a
|
|
[ 50%] Built target sublibrary1
|
|
Scanning dependencies of target subbinary
|
|
[100%] Building CXX object subbinary/CMakeFiles/subbinary.dir/main.cpp.o
|
|
Linking CXX executable subbinary
|
|
[100%] Built target subbinary
|
|
|
|
----
|