What I am looking for:
Download library
Extract It
Apply custom patch
Run configure
Run build command
What library I am trying to build are:
Openssl
Boost
Thrift
C-ares
Curl
Pcre
Nginx
ICU
JsonCPP
I think I can do these things using external module: http://cmake.org/cmake/help/v2.8.8/cmake.html#module:ExternalProject
But I have following question?
I have different type of build and with different directory. Is it
going to build all these library for every different target? If yes
it will be painful as all these library take one hour to build. Is
there a way I can control it and it only build it once. As library
remains same for all these targets.
On switching directory to different name. Cmake force everything to
be rebuild-ed. Will it be same for external library. If yes? How to
solve this problem. I don't want to rebuild the library if I am not
changing them and want to use them while switching to different
branches without building them.
Yes, you can use CMake's ExternalProject feature to accomplish what you want to do.
When using cross-compilation in combination with external projects, the source code will be built once for each toolchain. You could avoid rebuilds if you checked in the results of the build into a source-control system, and re-checked it out on each new person's machine, but I do not recommend this. Instead, have one of your "set up new computer" tasks actually be allowing the compilation to run overnight, which will also act as a test that the machine is actually usable. That set-up task can be launched by a system administrator prior to a new hire's arrival, or you can leave it to the new hire, as circumstances require.
I'm not completely certain what you are asking in your second question, but if the library is unchanged, CMake will detect that it is unchanged and not recompile it. Typically, the source code would be in a single directory tree: each compiled version would be built in a distinct location. Thus, developers can access any compiled version at any time just by switching directories. This is particularly helpful because it allows you to mount these directories over NFS to embedded hardware, et cetera.
Related
I am trying to build the latest GNURadio package on my development system. Unfortunately this system configuration is tightly controlled and I can't just install new packages of software on it as it is used to develop a product and all development systems are kept in lockstep. We are currently on an older version of RedHat.
While I cannot modify the system includes I can download and use newer versions of packages locally (in non-system directories) as long as that doesn't affect the product build/debug environment. Normally this isn't a problem.
However, when building GNURadio I found that our development platforms use an older version of the Boost libraries than is required to build GNURadio. So, I got the latest version of Boost and extracted it into my local (home) directory. I found several directions for, I thought, instructing CMake to use additional include directories. Unfortunately, this hasn't seemed to work with the Boost libraries. CMake keeps complaining that it finds the older version of Boost and not the newer one I have extracted locally.
I have tried using
-DCMAKE_CXX_STANDARD_INCLUDE_DIRECTORIES=<dir>
and
-DCMAKE_CXX_STANDARD_INCLUDE_DIRECTORIES_BEFORE=<dir>
and this had no effect. I then tried adding the following to the top-level CMakeLists.txt file:
SET(CMAKE_INCLUDE_DIRECTORIES_BEFORE ON)
SET(CMAKE_CXX_STANDARD_INCLUDE_DIRECTORIES <dir>)
or, even
include_directories(BEFORE <dir>)
Again, no joy.
I did a bit of digging and found that there is a GrBoost.cmake module and it had an additional configuration for the boost directory so I added this:
list(PREPEND BOOST_LIBRARYDIR "<dir>")
to the top of the file. Again, no luck.
I've never used CMake before (and I'm not really keen on learning yet another build system if I don't have to - our company just switched to bazel and I am coming up to speed on that) so I am flying blind here.
What do I have to do to get CMake to look in my local directory to find the Boost stuff I downloaded?
Ok. As it often happens, just after asking the question I was able to find an answer.
It turns out that there is a command-line option to CMake (CMAKE_PREFIX_PATH=<dir>) where you can specify additional base paths to search for CMake config files. I just added this to the command-line and it was found just fine.
I wasn't even aware that Boost came with such config files. Live and learn.
#vre's comment would have probably worked just as well (maybe better, in fact).
It's said that library authors should ship their library with a config-file instead of a plain find-module.
Basically config-file are to be installed with the associated library on the system and can be used transparently by the user, whereas find-module is written by the user by his own when he finds out that the library hasn't any config-file.
But, what if I'm sure that my library will never be installed?
I'm doing embedded system development and it doesn't make much sense to install my static libraries on the system.
Different modules are organized as static libraries and handled by each project with git submodules.
Is there any way I can use config-files even in this scenario? Or, as library author, I should write a example of vanilla Find-module and say to client code "Take and copy this to your CMAKE_MODULE_PATH"?
Or maybe just tell the client code cmake to call add_subdirectory?
I want to use KDL (Kinematics and Dynamics Library) in robot control box. But robot control box uses SCons as their build system while KDL uses CMake.
It turned out that the control box doesn't have CMake installed. Should I install CMake in the control box? Or write SCons file for compiling KDL?
====================================================
My question is ambiguous. Sorry for that. And unfortunately, I cannot show the link of Control Box, it's not public. Here is link of KDL installation manual.
http://www.orocos.org/kdl/installation-manual
Let me make it more clear.
Forget all of previous question above and all about Control box, KDL. Let's say that you want to use one library. But the library can be built using CMake according to installation manual. Your PC doesn't have CMake installed but it has SCons, and unfortunately you should not install CMake on your PC.
If you can only use SCons, what can you do?
I know this situation is not usual, I want to know your opinion.
To answer your initial question: Yes, you should always try to install CMake, if that is a build requirement for you library and if you need to build that library from the sources.
To answer your later question: Replacing or rewriting the build system scripts is a major effort and not advisable. In general there is no script to convert build-systems. Such script might help to make the manual transformation. If you have a look at LLVM's effort to replace Autotools by CMake or Boost replacing it's own build system by CMake, you find out it takes several people several years and still not everybody is satisfied.
Often you don't need to build the library yourself. Either there are already built packages from the project directly of from your distribution (Debian etc. packages) or third party packagers like Mac Ports or NuGet.
In your case KDL provides Debian/Ubuntu packages.
Additional KDL is part of ROS, which is experimental in Homebrew for OS X.
I wrote a piece of software which works well on my own box. It has been a headache to get it onto another box, though.
The main problem is that there is a library which it uses which is not a library covered by apt-get; it's called pngwriter. And pngwriter is also very finicky, and it is not very easily installed. It also has version compatibility issues. To get around all of that, I thought it would be great to include the source for pngwriter with my project, and have CMake go ahead and make pngwriter with the rest of the code.
So my main question is: Is this type of deployment canon? Should CMake call the makefiles that the developers of the software already wrote, and then use FIND_PACKAGE locally, or will I need to rewrite all of their makefiles so that I can use ADD_LIBRARY?
I'd recommend using the ExternalProject_Add function.
The docs are OK, but there is a decent article which explains things in a bit more detail. From this article:
The ExternalProject_Add function makes it possible to say “download this project from the internet, run its configure step, build it and install it”
Bear in mind that you can skip the install step altogether, or you could choose to install to a location inside your own build directory.
Can cmake configuration files also be used to automatically extend the system PATH variable to include the directory paths to all the installed executable applications and if it is possible (and a standard practice), how can I do this?
This way, as soon as I configure all the CMakeLists.txt files and everything compiles (and hopefully runs) nicely, I can start using the applications, and the path configuration would be packaged together with the build process. I am working with Linux and my code is written in C++, but since cmake is cross-platform, the question extends to other systems as well.
I'm unaware of any capability in CMake to do this. However, we based what we do what Cantera does. They upgraded to SCONS recently instead of their old build system, but the idea still applies.
Anyway, there's a script that CMake configures with the paths during the configure step and then installs somewhere. So once built on Linux, one would run make install then source ~/setup_cantera and it sets up all the variables needed.
We do the same thing for our libraries built with CMake. It's possible to detect which shell the user is running and configure an appropriate template script.