Add basic support and documentation for CMake build system

[ParticleG]

No description provided.

[masatake]

Thank you. Could you tell me how to build libreadtags with your change?
I'm using Fedora. On the platform, cmake command is available.
I would like to add 'building libreadtags with cmake' to the test cases run on GitHub Actions.

[ParticleG]

Thank you for your reply. I only use the main source files (readtag. c and readtag. h) to build into the static library. I currently do not have a Linux development environment, but you can try building it using the following command:

cd ${source_dir}
mkdir build_debug
cmake -DCMAKE_BUILD_TYPE=Debug -S . -B build_debug
cmake --build build_debug --target libreadtags -j ${cpu_thread_count}

[ParticleG]

I'm currently configuring my WSL environment, I have never used autoconf or automake before. Can you provide me with a generated makefile? If you can also provide me with a makefile for the test directory, I should also be able to complete the CMakeList.txt for the test directory.

[masatake]

Unlike ctags itself, I would like to keep libreadtags compilable with C99.

[ParticleG]

I've just found AC-PROG-CC-C99 in configure.ac. I'll update that.

[masatake]

Could you tell me the use case of the file?

If you assume cmake as an alternative build system to autotools<1>, I expect cmake to provide libreadtags.so with soname and an install target.

If you assume cmake is just for building the library at a specified directory<2>, maybe the current version you submitted here is enough for merging.

[ParticleG]

Could you tell me the use case of the file?

If you assume cmake as an alternative build system to autotools<1>, I expect cmake to provide libreadtags.so with soname and an install target.

If you assume cmake is just for building the library at a specified directory<2>, maybe the current version you submitted here is enough for merging.

cmake could create an install target with install() method, and canbe executed with cmake --build ${build_dir} --target install. But I currently don't have the makefile generated by the autotools for CMake coding reference.

Current CMakeList.txt is enough for other developers to use libreadtags in their CMake project as a dependency library

[ParticleG]

I am not very familiar with the autoconf+automake system. Based on my search results, the vast majority of configuration parameters should be in configure.ac and makefile.am? If that's true, maybe I could try to write an install target

[ParticleG]

I'm using the command in the .circleci folder to configure the project. I see the LT_VERSION is [2:2:1] which would result in libreadtags.so.1.1.2, but the project version is 0.3.0 in AC_INIT step. May I ask why they are not the same?

[ParticleG]

I've updated README.md for how to build & install a shared lib. If you follow these commands, it should generate libreadtags.so and corresponding sonames (Current are libreadtags.so.1 and libreadtags.so.1.1.2), and install to the /usr/local directory.

If there's anything still missing (like installing man or other stuff), just tell me to add them

[masatake]

I'm using the command in the .circleci folder to configure the project. I see the LT_VERSION is [2:2:1] which would result in libreadtags.so.1.1.2, but the project version is 0.3.0 in AC_INIT step. May I ask why they are not the same?

LT_VERSION specifies the version of the library interface.
So even if we add a commit, we will not update the LT_VERSION as far as the interface is not changed. e.g. fixing a bug in a test case.

Could you give me time? I must understand your changes well.

[ParticleG]

I'm using the command in the .circleci folder to configure the project. I see the LT_VERSION is [2:2:1] which would result in libreadtags.so.1.1.2, but the project version is 0.3.0 in AC_INIT step. May I ask why they are not the same?

LT_VERSION specifies the version of the library interface. So even if we add a commit, we will not update the LT_VERSION as far as the interface is not changed. e.g. fixing a bug in a test case.

Could you give me time? I must understand your changes well.

Of course

[ParticleG]

I'm using the command in the .circleci folder to configure the project. I see the LT_VERSION is [2:2:1] which would result in libreadtags.so.1.1.2, but the project version is 0.3.0 in AC_INIT step. May I ask why they are not the same?

LT_VERSION specifies the version of the library interface. So even if we add a commit, we will not update the LT_VERSION as far as the interface is not changed. e.g. fixing a bug in a test case.

Could you give me time? I must understand your changes well.

I forgot to commit README.md, sorry. Now you could try building it with instructions in README.md

[masatake]

I'm sorry for working on this pull request so slowly.
I cannot find a bulk time to concentrate on this topic.

https://github.com/openSUSE/libsolv/tree/master may have all I must study to apply cmake to libreadtags.

I wonder we should prepare FindLibReadtags.cmake like https://github.com/openSUSE/libsolv/blob/master/cmake/modules/FindLibSolv.cmake .

My concerns (and interests):

• Unify the places where the maintainer specifies various versions.
• Run the test cases as we do in autotools. (both locally and CI/CD environments)
• Generate and install libreadtags.pc as we do in autotools.
• Prepare make install target as we do in autotools.
• Prepare FindLibSolv.cmake and the way to install it.
• ...

[ParticleG]

I'm sorry for working on this pull request so slowly. I cannot find a bulk time to concentrate on this topic.

https://github.com/openSUSE/libsolv/tree/master may have all I must study to apply cmake to libreadtags.

I wonder we should prepare FindLibReadtags.cmake like https://github.com/openSUSE/libsolv/blob/master/cmake/modules/FindLibSolv.cmake .

My concerns (and interests):

• Unify the places where the maintainer specifies various versions.
• Run the test cases as we do in autotools. (both locally and CI/CD environments)
• Generate and install libreadtags.pc as we do in autotools.
• Prepare make install target as we do in autotools.
• Prepare FindLibSolv.cmake and the way to install it.
• ...

Actually, if we prepare CMakeList.txt properly, other CMake projects just need to use find_package method to load this package, see Finding Packages. But if you use CMake method FetchContent to add libreadtags to your project, then current changes should be enough. I've nerver tried to create proper "CMake Package Configuration Files", since I'm coding on Windows and use vcpkg to manage CMake packages. Maybe I'll try that in my spare time.

By the way, OpenSUSE's CMake standard is too old (2.x.x) which is deprecated according to CMake official docs. If you want to learn more about CMake, you should look for something more modern (> 3.5), like IXWebSocket, it also have FindXXX.cmake in it FindDeflate.cmake

[masatake]

Sorry for making you wait so long.
Looks good. The changes for README.md is excellent. All I wanted to know is written in the changes.

I'll take over this to adjust minor things.
See #53.