[CMake] Help request for hierarchical directory example

[David Aldrich]

Hi Eric

Thanks very much for your answer. I understand now.

David

On Fri, Oct 18, 2019 at 12:57 PM Eric Noulard <eric.noulard at gmail.com>
wrote:

>
>
> Le ven. 18 oct. 2019 à 12:53, David Aldrich <david.aldrich.ntml at gmail.com>
> a écrit :
>
>> Hi
>>
>>
>>
>> I'm learning how to use hierarchical directories in CMake and am trying
>> to get an example to work that I saw on YouTube. The example isn't doing
>> what I expect so I would be grateful for some help in understanding why.
>>
>>
>>
>> I am running CMake 3.10.2 on Ubuntu 18.04 (Microsoft WSL) and using make.
>>
>>
>>
>> I have a project called 'cmake-good' that should build library
>> 'libsay-hello.a' and executable 'cmake-good'.
>>
>>
>>
>> Here's the directory tree (excluding CMake artifacts which I don't think
>> I need to show):
>>
>>
>>
>> ├── CMakeLists.txt
>>
>> ├── build
>>
>> │   ├── CMakeCache.txt
>>
>> │   ├── CMakeFiles
>>
>> │   ├── Makefile
>>
>> │   ├── cmake_install.cmake
>>
>> │   ├── hello-exe
>>
>> │   │   ├── Makefile
>>
>> │   │   ├── cmake-good
>>
>> │   └── say-hello
>>
>> │       ├── Makefile
>>
>> │       └── libsay-hello.a
>>
>> ├── hello-exe
>>
>> │   ├── CMakeLists.txt
>>
>> │   └── main.cpp
>>
>> ├── say-hello
>>
>>     ├── CMakeLists.txt
>>
>>     └── src
>>
>>         └── say-hello
>>
>>             ├── hello.cpp
>>
>>             └── hello.hpp
>>
>>
>>
>> Here are the CMakeLists.txt files:
>>
>>
>>
>> 1) Top level CMakeLists.txt:
>>
>>
>>
>> cmake_minimum_required(VERSION 3.10)
>>
>> project(MyProject VERSION 1.0.0)
>>
>> add_subdirectory(say-hello)
>>
>> add_subdirectory(hello-exe)
>>
>>
>>
>> 2) hello_exe/CMakeLists.txt:
>>
>>
>>
>> add_executable(cmake-good main.cpp )
>>
>> target_link_libraries(cmake-good PRIVATE say-hello)
>>
>>
>>
>> 3) say-hello/CMakeLists.txt:
>>
>>
>>
>> add_library(
>>
>>     say-hello
>>
>>     src/say-hello/hello.hpp
>>
>>     src/say-hello/hello.cpp
>>
>> )
>>
>> target_include_directories(say-hello PUBLIC
>> "${CMAKE_CURRENT_SOURCE_DIR}/src")
>>
>>
>>
>> My problem is that I expect to see:
>>
>>
>>
>>     hello-exe/cmake-good
>>
>>     say-hello/libsay-hello.a
>>
>>
>>
>> but I see:
>>
>>
>>
>>     build\hello-exe\cmake-good
>>
>>     build\say-hello\libsay-hello.a
>>
>>
>>
>> Why is that?
>>
>
> Because build/ is your build directory and you apparently did an
> out-of-source build (which is good practice)
> see :
> https://gitlab.kitware.com/cmake/community/wikis/FAQ#out-of-source-build-trees
>
> You should have done something like:
>
> cd cmake-good/build
> cmake ..
> make
>
> In this case everything the build is generating (CMake artefact, build
> artefact etc...) gets written build/
> the directory hierarchy in build will have the same structure as your
> source tree.
>
> This is an expected behaviour.
>
>
>
> --
> Eric
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://cmake.org/pipermail/cmake/attachments/20191018/b3f5d58d/attachment-0001.html>