CMake won't link when moved to 64-bit system - cmake

I had been using CMake without problems when I discovered my Ubuntu was installed as 32-bit even though my processor is actually 64-bit. Whoops.
I reinstalled Ubuntu and the various dev packages I was using. Now when I run make I get errors like this:
[ 1%] make[2]: *** No rule to make target `/usr/lib/i386-linux-gnu/libQtGui.so', needed by `/home...
/usr/lib/i386-linux-gnu/libQtGui.so` doesn't exist but /usr/lib/x86_64-linux-gnu/libQtGui.so does.
I have run ccmake to reconfigure and regenerate the makefile and run make clean but it's still looking for 64-bit libraries. If I expand the ccmake options I can see the 32-bit library path in various variables.
I have created a new build directory and run ccmake from scratch and this works but now I have to remember all the nondefault settings I put in and reproduce them in the new build environment.
I'd rather just "upgrade" the CMake setup to 64-bit, preserving my own flags. Is this possible?

Start with a new CMake cache:
rm CMakeCache.txt

If you don't like removing your Cmake cache, you can edit it and search-and-replace to modify the paths of libraries.

Related

clion wsl "CMake 3.20 or higher is required. You are running version 3.16.3"

so I just downloaded wslusing the wsl --install command using PowerShell
now I'm trying to connect it to Clion which works
i cant add images so here is a link to it
but when i'm tying to build the project i get this error
"CMake Error at CMakeLists.txt:1 (cmake_minimum_required):
CMake 3.20 or higher is required. You are running version 3.16.3"
my cmake file:
cmake_minimum_required(VERSION 3.20)
project(ex2 C)
set(CMAKE_C_STANDARD 99)
add_executable(ex2
ex2.c ex2.h
main1.c
main2.c)
i tried updating wsl using wsl --update (in powershell)
The CMake installation inside the WSL is used. Unfortunately currently snap doesn't seem to be available in WSL, but installing the latest CMake version isn't too complicated nonetheless:
(optional) uninstall the old cmake installation in WSL; personally I don't see any benefit in multiple CMake installations, but there may be valid reasons for this. Most likely this will just makes the use of cmake more complex, since you need to remember which cmake version is used.
Download the appropriate cmake version from the cmake website ( https://cmake.org/download/ ). The version to choose is the tar.gz file under binary distributions for the x86_64 target. To get version 3.21.4 (currently the latest release), you can download the file from https://github.com/Kitware/CMake/releases/download/v3.21.4/cmake-3.21.4-linux-x86_64.tar.gz (Identical to the link on the CMake download page).
Unpack the archive from WSL. Navigate to the directory where you want the cmake installation to recide. This will add the cmake-3.21.4-linux-x86_64 directory containing all the files required to work with cmake to the current working directory. Let's assume you want to add the cmake files to the /opt directory. Furthermore let's assume the windows user name to be fabian, C: to be the primary hard drive and the download to be saved to the Downloads directory in the user directory:
cd /opt
tar -xf /mnt/c/Users/fabian/Downloads/cmake-3.21.4-linux-x86_64.tar.gz
(optional) make CMake available without specifying the path; this could be done as described here: https://unix.stackexchange.com/questions/3809/how-can-i-make-a-program-executable-from-everywhere ; don't do this, if an existing cmake installation is already available in the command line assuming you did install cmake to /opt, the cmake binary recides at /opt/cmake-3.21.4-linux-x86_64/bin
You should now be able to use cmake specifying either the full path to the executable (/opt/cmake-3.21.4-linux-x86_64/bin/cmake assuming you used the /opt directory) or directly via a command after opening the WLS commandline again (provided you followed step 4).
Now the only thing left to do should be telling CLion about the location of the cmake executable. Note that I haven't tested this, since I don't use this IDE. It's working fine using Visual Studio Code though...

How can I manage the installation directory with CMake when cross-compiling?

I am cross-compiling a C library using CMake and a toolchain file. My toolchain file sets CMAKE_SYSROOT to the appropriate value so compilation works with no issues. However, when installing, the library does not install to the directory pointed to by CMAKE_SYSROOT. I can achieve that effect by running make install DESTDIR=xxx though.
I understand that there are two separate concepts here:
The cross-compilation toolchain, which consists of binaries that can be run on my local architecture
The CMAKE_SYSROOT which is the root directory of a target-architecture filesystems, containing header files and libraries, passed to e.g. gcc through the --sysroot flag.
I have two questions:
Is it a good idea to conflate the sysroot where my cross-compilation toolchain lives, with the sysroot where all my cross-compiled libraries will be installed? It feels to me like it should be the same, but am not sure, and to CMake it appears they are distinct concepts. Update: answered in the comments below, these are indeed distinct concepts.
What is the modern CMake way to specify the installation directory when cross-compiling like described above? Update: I believe this should be the same as CMAKE_SYSROOT, and I feel CMake should offer a way to only define this once somewhere.
Thanks!
There is no interference between sysroot and install directory (prefix).
Sysroot is given by CMAKE_SYSROOT variable and denotes prefix for tools used during build process.
Install directory(prefix) is given by CMAKE_INSTALL_PREFIX variable and denotes the path, where the project will be used upon installation. E.g. with install prefix /usr/local the project's executable foo expects to be run as /usr/local/bin/foo.
Note, that with default installation procedure, CMake installs files to the host machine. For install files onto the target machine, this procedure is needed to be adjusted. Parameter DESTDIR=xxx for make install is a way for install files directly to the target machine. Another way is to create a package (e.g. with CPack) on host, and install that package on target machine.
Note, that in the above paragraph it is irrelevant, whether cross-compilation took a place or not: it is possible to build the project on one machine and install it to the other, but similar one, without any cross-compilation.

Compiling latest release of CppUTest (3.7) with MinGw, pthreads missing

I'm trying to use CppUTest in Windows, first step is to get it to work and I already have problems. These are the things I've tried:
First Approach
With CMake, using the cmake GUI I can do the configure and generate command and I get something in the output directory, but no binaries and no libraries, just a bunch of cmakefiles. The CMake GUI says everything went OK during the configuration and generation steps, however the libraries (.lib files) are not generated in the output directory... is there something I am missing? I've never used CMake before.
Second approach
With MinGW and msys alone, running cmd in Windows and executing a MinGW shell by typing sh in the Windows terminal, afterwards I execute the following commands:
cd <CppUTest folder>
mount c:\mingw /mingw
./autogen.sh
./configure
make
The build process starts but it fails with a message indicating that pthread.h was not found in MinGW directory. If I install the pthread-win32 package with the MinGW package manager and repeat the same steps as above the build process starts but fails with a message indicating that the structure timespec is defined in time.h and pthread.h.
I've tried to follow this same procedure with CppUTest 3.6 and it works perfectly fine, I get the .lib files, so I guess I will have to continue with this for now.
Does anyone know how to build CppUTest 3.7 (latest release) with MinGW or CMake?
In the end I used Cygwin to compile it, I couldn't find a way to compile it with MinGW properly, I added a dirty trick to make it compile under MinGW (handled the timespec redifinition) but chances are that is going to cause issues.
Just make sure that you use Cygwin aswell to compile your tests, something that I found out after making this question (https://www.youtube.com/watch?v=oVmd0P85D8o).

Why -DCMAKE_EXPORT_COMPILE_COMMANDS does not create compile_commands.json file

My cmake --version is 2.8.12.2.
I configure my project build with these commands:
cmake ../klein/ -DBUILD_KLEIN_DEPS=1 -DCMAKE_EXPORT_COMPILE_COMMANDS=1
cmake ../klein/ -DBUILD_KLEIN_DEPS=1 -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
cmake ../klein/ -DBUILD_KLEIN_DEPS=1 -DCMAKE_EXPORT_COMPILE_COMMANDS=on
CMAKE_EXPORT_COMPILE_COMMANDS=1 cmake ../klein/ -DBUILD_KLEIN_DEPS=1
From a clean build, and from a directory with an existing successful build. And want to see the compiler_commands.json file, but it does not appear.
At which moment should it be created: after cmake, or after make command? Where should it be in ./, or in ../klein directory? My cmake does not say anything about this option while it always complains about unused build variables.
Should it work from in a "dirty" directory, where I've performed one successful build, or does it work only on a fresh run in an empty folder?
Edit:
I use a default generator "Unix Makefiles" on my ubuntu linux machine
Edit2:
I'm not an author of the project under the question (I just want to explore it with rtags which requires compile_commands.json file), and I'm not very familiar with CMake mechanics. However, the CMakeLists.txt is probably configured as a super-build (it indeed downloads and builds dependencies - like llvm, z3, ...), and it includes ExternalProject, however it also builds the project itself (klein) from sources. So it's a mix, as I would say.
Can you specify what generator your using? A quick scan of the cmake source from version 3.1.0 suggests that this command is still only available in the following 2 cases.
if(CMAKE_GENERATOR MATCHES "Unix Makefiles")
and
if(CMAKE_GENERATOR MATCHES "Ninja")
if you're using Visual Studio directly you're out of luck unless you want to add a patch to CMake. Otherwise, I know many Windows developers who've gone to Ninja. One advantage is that it's vastly faster than Visual Studio for building. If you are, in fact using Ninja or Unix Makefiles, then it's worth digging deeper.

What is the CMake install time?

A quote from the official documentation:
"Specify rules to run at install time."
What exactly is install time?
The problem for me: I am on Linux, software is installed from packages that are just dependencies and data. There is no CMake that can do anything here. So installation time of software is out of scope from CMake. So what exactly do they mean?
Building a CMake project can roughly be divided into three phases:
Configure time. This includes everything that happens while running cmake itself. This phase is concerned with inspecting certain properties of the host system and generating the specific build files for that platform under the selected configuration.
Build time. This includes everything that happens while actually building your project from the files generated by CMake (like, when running cmake --build or make). This is where all of the actual compilation and linking happens, so at the end of the build phase, you have a usable binary.
Install time. This includes everything that happens when running the INSTALL target generated by CMake (like, when running cmake --build --target install or make install). This takes care of copying the binaries that were generated into the build tree to a different directory. Note that the build tree contains a lot of stuff that is no longer needed once the build is completed if you are only interested in running the binary. Examples include all intermediate build artifacts, like the build files generated during the configure phase or the intermediate object files created during the build phase. Furthermore, the install phase might include additional steps to ensure that the binaries produced during the build are portable. For instance, on Linux systems you might want to remove the build directory from the shared library search path in the binary and replace it with a portable equivalent. So the install phase might do more than just copy all the important files to a new directory. It could also include additional steps that change the binaries to make them more portable.
Note that the last phase is optional. If you do not want to support calling make install but prefer another deployment mechanism, you simply don't use the install command in your CMake script and no INSTALL target will be generated.
I'd like to expand the answer, which ComicSansMS gave you, a little bit.
As he mentioned - CMake generates an extra target called install for the make tool (when you use a Makefile-based generator).
It may look weird for you as a package system is used for Linux. However the install target is still useful or even necessary:
When you develop your application you may need to install (move binaries and possibly some include files) to a certain location so some of your projects may see each other. For example, you may develop a library and a set of non-related applications which use it. Then this library must be installed somewhere to be visible. It doesn't mean you need to put it to the /usr directory; you may use your /home.
The process of Linux package preparation requires an install step. For example, the RPM packaging system does three main steps when the rpm package file is being built: the project is configured, then is compiled and linked and finally is being installed to a certain location. All files from this location are being packed to the rpm file.