I'm using cmake and it's a wonderfull tools. I'm using it under Linux with the Ecplise IDE. But, there are something I could do easily when I was working on Windows through Visual Studio, and I don't know how to do it with cmake :
I want to build the ".o" of a single ".cpp" file of my project. I can't find a way to do that easily (i.e. without invocate gcc directly).
I tryed the following command line
make CMakeFiles/project.dir/src/module.cpp.o
But I doesn't work... Have you got any idea how to do that ?
Simply write
make module.cpp.o
in the build directory (where you have executed cmake)
Related
I'm currently learning C++ and I'm working on a small project. I was wondering how I can generate an executable of my project. I'm not sure how to do it, I'm using Ubuntu 20.04
I've googled it but I can not find any instructions on how to do it.
Well. If you are using CLion, you can just create a new project, and check the CMake file that CLion generate. Something like this:
cmake_minimum_required(VERSION 3.20)
project(Test)
set(CMAKE_CXX_STANDARD 14)
add_executable(Test main.cpp)
And in that file there was a line with a function called add_executable, in that function you set first the exe name and then the source files. And just run the project in CLion. By default CLion create a directory calle "cmake-build-debug" where the exe file are located.
If you want to add more libraries, change the binaries source directory and more. You will need learn CMake. Also you can use CMake standalone whiteout CLion, you just need install it sudo apt-get install cmake and use then in the terminal.
Expanding over #Steback's answer:
First, a clarification: an executable file is a file that can be executed by the system. It (roughly) contains assembly commands. Under Windows executable files are marked with an .exe extension. Under linux, they are usually extension-less.
To generate an executable file from C / C++ code you ("only") need a C/C++ compiler. A default / pre-installed one on Ubuntu is gcc / g++ (whereas on Windows you need to actively install one).
CLion is an IDE and (exactly like any other IDE) can run the compiler for you. IDE (stands for Integrated Development Environment) is a program which incorporates (minimally) a text/code editor, a compiler and a debugger (all of which it invokes normally via command line, just as you can do yourself).
CLion is an advanced (and excellent) IDE. In CLion, the way you specify how exactly it should invoke the compiler is via the CMake language (not to be confused with the unix tool make which chiefly only knows to run commands conditionally on file modified date).
CMake code should be placed in a file named CMakeLists.txt in the project root directory (sometimes CLion creates this file for you automatically). A minimal cmake project looks like
# Specify cmake language version to use for this file
cmake_minimum_required(VERSION 3.10)
# Specify any name for the project
project(NameYourProject)
# A name for your executable file and the code files needed to build it
add_executable(YourExecutableName source_file1.cpp somefolder/source_file2.cpp header_file.h)
Of course this is just a very minimal example. The CMake language is a powerful language to specify build processes, with cross-platform support. You can look it up / learn it someday.
When giving the "build" command to CLion it will now do two things:
use the cmake tool to generate a set of commands for gcc/g++ (this is called "cmake configure" + "cmake generate") - according to what you wrote in CMakeLists.txt
run the generated commands to hopefully build your executable.
As a beginner, you may be better off first trying to run the compiler yourself via the command line to see what it does. You can also opt for a different IDE (e.g. CodeBlocks, eclipse, Dev C++) where you specify what you need the compiler to do via a GUI and not via CMake (although CMake is arguably more convenient).
I'm using Dev C++. When I run and compile it, it automaticcally generate a .exe file. Just install it and open ur file with it and compile it. Should work good.
I have a CMake project. It is a crossplatform project developed by a team of developers. Visual Studio and other make files are inside version control for library release and external developers.
Each time a file is added we need to recompile all project files for all platforms. How do I force CMake to generate new project files for all systems at once (if possible from inside CMakeLists.txt, not as command line arguments)?
I think it doesn't make sense for this to be possible within the CMakeLists.txt file. CMake is a makefile generator. Everything in the CMakeLists.txt file is configuring the makefile, and it can also be repurposed to make project files.
If the CMakeLists.txt file could also request to generate a different kind of makefile... it would be different from every other command in the CMakeLists.txt file in that it isn't describing the currently selected makefile.
If I were you I would just make a shell script, or a simple makefile, separate from CMake, which rebuilds each of the project files, by invoking CMake from command line with appropriate parameters.
Is the goal of the versioned CMake produced build scripts to not force developers to install CMake?
In any case: it's best to use the right tool for the right job. CMake is for producing build-files and the little scripting necessary to do so. Use a scripting environment (Bash, cmd.exe) to run CMake as necessary for all your platforms.
This keeps the CMake files clean (and readable, CMake scripting is hard to read) and provides clean separation of concerns.
I want to write a clang tool that can run on C++ projects that I have that already exist which use Makefiles to build. The problem is, it seems as though any project that is going to be put through a clang AST must be built using cmake so that it can get a compile_commands.json file. Is there a way to do this for projects that don't use cmake? Or is there a way to build Makefile projects with cmake?
You might be able to use this script with cygwin:
https://github.com/woboq/woboq_codebrowser/blob/master/scripts/fake_compiler.sh
for around 5 consecutive days i have been trying to set up my computer with the c++ environment for programming with libraries such as sdl,glm,opengl. its important for us to be able to run it on unix machines on presentations so im running with cmake.
i finally got it to work with the cmake-gui, i wont even bother trying anymore with any IDE.
i specified my folder project and where to build the binaries, i got a folder "CMakeFiles" along with a txt "CMakeCache", a CMAKE file "cmake_install.cmake" and a file "Makefile". also in my folder "CMakeFiles" there are lots of other folders such as "CMakeTmp", "CompilerIdC", "CompilerIdCXX etc" and in both folders "Compiler*" has each an .exe which doesnt work! so where is my wanted executable?
i opened cmd and navigated to my folder and tried to write "make" as we are supposed to do according to the intruction. alas, it didnt work very well. hoping you could share your wisdom and help a newbie like me!
so what exactly is needed for compiling projects containing additional libraries? so far i have a compiler, Mingw32, the latest CMake and using the cmake-gui for extracting the binaries but gets makefiles.
EDIT:
hrrm. is it only me who gets these kind of problems? i can add that i have look thorough about 10 tutorials and 90% of the steps are similar (if compiling with VS which i tried at first):
Download latest SDL
Make a folder on e.g C:\SDL with two folders, include and lib
Copy the libs and includes from the downloaded SDL
Make new VS project, open VC++ directories and add lib/incl folder on e.g C:\SDL
Add to linker SDL.lib and SDLmain.lib (i made sure they got linked, no problem here)
Change system to WINDOWS (optional if you dont want two windows)
Added include to "additional libraries"
Put the SDL.dll file (which i got from the latest SDL) in my C:\windows\system32(64SysWoW)
and also in my project file.
so what i am actually looking for is gettning the CMake to work, since it generates and builds sources successfully (with the gui) and i feel im closing in. do i need to add any additional libraries from sdl to my compiler mingw32 and/or cmake?
if you run cmake by command:
cmake -G "Visual Studio 14 Win64" path\to\source\dir
you need to run this command to continue(in Visual Studio Command Prompt):
msbuild Project.sln
either if you run cmake:
cmake -G "NMake Makefiles" path\to\source\dir
you need to run this cmd to continue(in Visual Studio Command Prompt):
nmake
You were almost there with Visual Studio. Select Visual Studio as target. Open the generated project in Visual Studio, build it. (just like you alread did). Then, instead of trying to run BUILD_ALL, run a real project that creates an executable, it should also be in that list. Just right click it and 'play' it.
If you still get errors, post them in detail including what you did before the error. Note: a carefully configured cross platform CMake project (aka the CMakeLists.txt) should not require any fiddling with VC++ directories. It should work automagically, especially with well known libs such as SDL.
If I understood it correctly you want to use CMake in your project. I'm using CMake in all my projects. I won't give you exact step-by-step howto, since I use Arch Linux but I used it in Windows 7 too.
To make CMake find the libraries, it is often needed to set up the CMAKE_PREFIX_PATH environment variable so it points to the directories where dependencies of your project are installed.
Set you PATH environment varible so you can invoke you compiler and make just by calling by calling eg. make. I think you need to do than manually for Mingw32, for Visual Studio you can use the "Visual Studio Command Propt" which has these variables already set.
Run CMake with desired generator. To select the generator from command line use the -G switch. You will probably use one of the following (the ... means other options you want to pass to cmake)
For GNU make used in MinGW use cmake -G "MinGW Makefiles" ...
For NMake from visual studio use cmake -G "NMake Makefiles" ...
It is also possible to create a Visual Studio project but I do not recommend it, since it quite difficult to set up automatic builds then. I also had some problems with dependencies when I tried to use VS project.
change directory to your build directory (ie. the one where you called cmake, it contains the CMakeCache file) and run make or nmake
Quoting from "CMake support in Visual Studio":
Visual Studio 2017 introduces built-in support for handling CMake projects. This makes it a lot simpler to develop C++ projects built with CMake without the need to generate VS projects and solutions from the command line. This post gives you an overview of the CMake support, how to easily get started and stay productive in Visual Studio.
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My System: Windows Vista 64 bit
Library: Bullet Physics v2.78
Makefile Generator: CMake
Build system: MinGW command line, MinGW + CodeBlocks
Makefiles were implemented by command line and through CMake-generated Code::Blocks project
In both cases, the build fails near 30%. NOTE: I did have to switch the build executable in the Code::Blocks project from make.exe to mingw32-make.exe
First Failure: Demos\OpenGL\GLDebugFont.cpp -> GL/glut.h: No such file or directory
Second Failure (after commenting out the #include from the first) -> Demos/OpenGL/GlutStuff.h: same error
These failures happen when I build command-line OR through the generated C::B project.
Why can't it find GL/glut.h? "bullet-2.78\Glut\GL\glut.h" exists. Maybe there's a way I can tell it to find glut there?
NOTE: During the CMake makefile generation, CMake did tell me that "You are using the obsolete GLU package, please use OpenGL instead." It continued as normal with the Makefile generation. Maybe I need to define some environment variables? Maybe I need to configure something in Windows that CMake is looking for?
I would add a compiler search path in bullet-2.78/Glut, but Code::Blocks doesn't allow that if you're using a custom makefile (like a CMake-generated one).
UPDATE: I have been able to build the library itself, by building specific targets in the Code::Blocks project. However, I have been unable to build any of the demos or the benchmark test, since they all use OpenGL (and apparently glut.h). I would still like to compile those.