I'm using eclipse for the first time. I'm a seasoned VisualStudio user, so I'm trying to find similar functionality in eclipse. I have two projects, A and B. Project A spits out libA.a when it's done compiling. Project B links against libA.a. Here is my problem.
I compile project A then project B, everything is fine.
I make a code change to project A that requires a build of project A.
I try to build project B, but it states that no changes have been detected.
How do I make project B aware of the output of project A?? Currently I'm having to do a clean build of project B for it to re-link against libA.a.
Thanks.
EDIT: In my ProjectB->Path and Symbols->References tab, I have project A checked. This doesn't relink after project A is rebuilt.
Try the below settings:
Go to properties of Main Project → C/C++ General → Paths and Symbols → References
Tick all the dependencies.
You go into Project Properties of Project B, select Project References and make it reference (depend) on Project A.
Edit, appears to be a known bug
One can work around this problem by using the touch command.
In Eclipse, as part of C/C++ Build/Settings is the tab 'Build Steps'. In the pre-build steps command line, enter touch filename.
filename is any file in your application. This could be the file with main(). This could be a special file just for this workaround, touchdummy.c, which can be a tiny file, which compiles quickly.
When the application builds, even if you didn't change any sources, the touch command causes make to rebuild the application. If the library was rebuilt, then the application gets rebuilt with the new library.
One can read about how touch affects the date/time of the file here.
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/touch.html
Edit: The exact command in Eclipse would be touch ${ProjDirPath}/src/main.c
Edit: This command should work, but it appears that if the 'main' project did not change, the pre-build step is not executed. Also the touch command causes eclipse to prompt to reload the file it touched. A large annoyance.
Eclipse projects depend on each other by virtue of the checkbox in the project's properties (dependent projects?) which is how Eclipse decides which to build. You can set this yourself, but it's usually set when you change your Java build path.
By default at least with QNX C++ projects, it WILL NOT check for changes in other projects.
Right click on the project, and expand "check dependencies on/off"->"check user headers only"
It seems to work, roughly...
It appears to do a makedepends on the code, and adds *.d files to the output folder which are simply depends file that list the header files.
Note: these do not appear to get regenerated, and get out of date - I do not know how to regenerate them.
For Project A (library):
Properties>C/C++ Build>Settings>Build Steps>Post-build steps> touch -m ${ProjDirPath}/source/build/build_updated.cpp
You should create folder "source/build" firstly and don't add in that folder any other files.
For Project B:
Properties>Project References> check Project A
Properties>С/С++ General>Paths and Symbols>Source Location>Link Folder>Link to folder in the file system> find and pick "source/build" folder which you created for project A before.
Related
I am working with Eclipse Luna with CDT plug-in.
Whenever I build the project it keeps rebuilding all files, even if I just modify specific .cpp file.
I use project -> build project for the build.
I also removed build automatically option (and re-opened eclipse), but it did not solve the problem.
I've searched a lot for similar questions, but found none.
Are you using a manually-managed Makefile project, i.e. one that is not automatically-managed by the CDT plugin? If so, perhaps you could post your Makefile contents here, because there may be issues with the target dependencies in it.
The File | New | C++ Project | Executable option creates a project in which CDT automatically creates and updates the Makefiles itself - in this setup, the dependencies (while not perfect, because there are a few bugs in CDT in this respect) should be managed well enough so that it won't rebuild the entire project just because one file changed.
On the other hand, if you imported an existing project via the menu File | New | Makefile Project with Existing Code (which I didn't previously mention), then you would have had to copy the Makefile from the existing project manually, as CDT doesn't copy it for you, or you would have had to manually create a Makefile.
As I mentioned previously, if you posted your Makefile (feel free to 'sanitise' it by removing any personal information), we might be able to determine why it's rebuilding all files when you've only updated one of them.
I would have posted this as a comment reply to your last comment, #davidgrandson, but apparently there's a fairly short limit on the length of these.
I've a C++ project in eclipse which is version managed with git. I've a git submodule, which is another project I've written in C++. The submodule has its main function and my project has its own.
Eclipse chooses other main (from the submodule) to compile when I press build. Is there a way to choose which main to build in eclipse?
Update: I'm still working on the issue. Excluding resources from the project didn't help either. Will answer the question when I solve it.
Update 2: Solved at last. See my answer.
I have solved the problem, at last. The solution is not a simple and straightforward one, so I'm writing step by step:
First set your toolchain correctly from Properties -> C/C++ Build -> Tool Chain Editor -> Current toolchain. It's MacOSX GCCor Linux GCC for me.
Set your correct project source path. I've symlinked the files from projects I imported as submodules to my project, so setting the correct source directory didn't exclude any required files from my project. Setting is at Properties -> C/C++ General -> Paths & Symbols -> Source Location. Make sure you exclude the other submodules and symlink the required files to your project.
Change the name of the artifact (binary, library, etc.) to something different than the ${projName}, because when you have submodules, you will have a directory named as ${projName} inside your build folder. Setting is at Properties -> C/C++ Build -> Settings -> Build Artifact -> Artifact name.
After making these changes, your project should build automatically. Looks like eclipse makes all necessary checks during build, but doesn't warn you about the problems. I had to see all these problems with running make --always-build inside the Debug folder.
I am quite used to Linux development and Makefiles, and started using (Windows and) Visual Studio not so long ago.
What I want to do is (I think) quite simple, but I can't seem to find how to do it using Visual Studio.
I have to write an application, which I can divide into several independent sub-parts. I want to work incrementally, and create several projects that together with a main file will end up with my full project.
What I basically want is to be able to write a small project, have a main for it so that I can fully test it, and use it as a dependency for the next project. In this case, the smaller main would be deactivated (or I can comment it), and I would just change the startup project.
If I find a bug in a subset while writing my bigger software, I could just change the startup project and solve it at a smaller scale.
Well, that's what I do all day long in Python and Java.
I tried to create new projects into my project, but I always end up having linking problems, where my main projects knows about the files in the sub projects, but not the smaller ones, etc. . .
So, is there a guide somewhere I can find to work this way ?
Thank you
For individual projects:
Every individual project property sheet has a C++ options page. Here you can specify the 'Addional Include Directories' in a comma separated form.
Similarly, there should be a property sheet for Linker where you can specify the 'Addional Include Dependencies' and the names of the libraries it depends on.
For linker dependencies of the main executable:
Go to that main project, go to its properties, go to common properties and select 'Framework and References'. This should give you a list of all the projecs that are in your solution. Keep adding them and Visual Studio should add the right linker flags automatically for you.
Sorry, have no access to the computer now else would have provided exact steps. Visual Studio can get tricky sometimes but once you use it, you'll be amazed by what it can do for you. Personally, I love it.
Hope this helps.
Thanks to Vaibhav, I was able to find a solution:
I had to :
change subproject type to lib instead of exe
Add the subprojects as project dependencies in the main project (this just sets the build order)
Comment out the main of my subprojects, to keep only one active.
Add each subproject include directory in the include repos of the main project, so that the compiler can find the header files
Add the general directory as a dependency for the linker (in this case, it is not the debug/release folder of the subprojects, but the output directory of the complete project).
Add the names of the lib files of the subprojects in additional dependencies of the linker of the main project.
To make it simple, the project dependencies capability of VS2010 just changes the order in which the projects are built. . . I miss Eclipse.
If I find a bug and want to test on of the subprojects, I have to :
change the startup project to be the subproject I want to change.
uncomment the corresponding main
change the project type to be exe instead of lib to be able to compile it.
Debug, and do everything back again to continue working on my main project.
Quite boring, don't you think ?
Looks like you trying to do manual unit testing. Use something like Google.Test. You need to make test project for every lib.
We have directory with static libs projects. Another directory with tests projects. Every test solution contains one exe project and few existing lib projects. Every project have configured dependencies. You dont need to set additional dependencies of the linker manually (paths are evil, out dir for the lib file will be taken from project settings), open project properties with right mouse button, Common properties, Add new reference and select lib project. You only need to set additional include dirs.
When you find new bug - just open test project for the library with bug, add code which cause the bug, fix it, and be happy (and sometimes run all test). And even better - use TDD.
I cannot find the possibility to change the output of the built files. The only I've found deactivates the whole generated makefile process, which I don't want to.
Right-click on your project and choose Properties.
Go under C/C++ Build, under Settings.
Click on the Build Artifact tab.
Under "Output prefix", enter the directory that you want to contain your built file (including a trailing slash).
It looks like you'll also need to modify your Run / Debug Settings with the updated path.
(However, writing your own makefile really isn't hard, especially if you use Eclipse's generated makefiles as a starting point, and it can give you a lot more flexibility.)
I have a program which consists of multiple projects in eclipse (working under ubuntu and the projects being in c++), these projects consist of a main executable file, and other shared objects files and static libs.
I want all these projects when built to output their files to one common binary folder, instead of their respective debug folders. This is to make linking easier with the main executable. If there are better solutions please also feel free to share.
Unfortunately, I have found that the C/C++ Build tab does not allow you to set the build location unless you are creating your own makefile.
You've likely found that the Builder Settings tab under Project Properties>C/C++ Build is all grayed out in a default C/C++ project. This is because CDT nominates the internal builder by default for new projects. To change this, you can go to Project Properties>C/C++ Build>Tool Chain Editor and change the Current Builder to Gnu Make Builder. Next, go to Project Properties>C/C++ Build and change the Builder Type to External Builder. You can now opt to create your own makefile for the project, if you like; though I'd recommend leaving CDT to build the makefile automatically for now.
I have the same project requirements of outputting to a /project_path/bin (though I still maintain separation between Debug and Release builds). To do this, I perform a copy operation on the output as a post-build step.
To do this, go to Project Properties>C/C++ Build>Settings and select the Build Steps tab. In the Post-build steps under Command:, enter:
cp ${BuildArtifactFilePrefix}${BuildArtifactFileName} "/path/to/bin/directory/";
Obviously replacing the "/path/to/bin/directory/" as required.
I personally prefer to maintain my project files in a workspace/build directory; copying binaries to a workspace/bin directory and libraries to a workspace/lib directory. At first I found this copy workaround to be an inconvenience, but have come to appreciate it because it isolates the interstitial build files from the final binary/library.
For binaries, I would use:
cp ${BuildArtifactFilePrefix}${BuildArtifactFileName} "${WorkspaceDirPath}/bin/";
For libraries, I would use:
cp ${BuildArtifactFilePrefix}${BuildArtifactFileName} "${WorkspaceDirPath}/lib/";
I include the variable "${BuildArtifactFilePrefix}" because CDT includes "lib" as a default prefix for static libraries, which I actually prefer.
You just need to ensure that the target directory exists before building; Eclipse/CDT will not create the directory for you.
Also, just remember that these copies will be left behind in the /bin or /lib directory on clean, but overwritten on any subsequent rebuild.
Try Project->Properties
Under C/C++ Build->Settings you have a tab called Build Artifact.
Under there you have Artifact name. This defaults as ${ProjName}.
Modify this to specify a relative directory path to where you actually want the final file to end up. So could be ../../lib/${ProjName}
The intermediate files (.o and .d) will still build to the sub-directory (Debug or Release) but I guess it's better off if they are there anyway and it is only the finally built library for which you want to change the build path.
If you find it inconvenient typing the relative path like this, I use Environment to create environment variables with relative paths taking me back to a "root". One of this I have is ${LIBDIR} and this is a relative path from where the project gets built. It is usually used for linking in other libraries, but can also be used as a target. Then you would set Artifact Name to ${LIBDIR}/${ProjName} which works well if you use different directories for debug and release builds.
Go to
Project Properties -> C/C++ Build -> Settings -> (tab) GCC C++ Linker
The command line pattern is shown on the right side
${COMMAND} ${FLAGS} ${OUTPUT_FLAG}${OUTPUT_PREFIX} ${OUTPUT} ${INPUTS}
Put in front of ${OUTPUT}
${COMMAND} ${FLAGS} ${OUTPUT_FLAG}${OUTPUT_PREFIX} ${ProjDirPath}/bin/${OUTPUT} ${INPUTS}
or
${COMMAND} ${FLAGS} ${OUTPUT_FLAG}${OUTPUT_PREFIX} MyMainProject/path/bin/ ${INPUTS}
From https://www.eclipse.org/forums/index.php?t=msg&th=207500&goto=665566&#msg_665566
In my project the build path defaults to the Build Configuration name, so I could use a ${ConfigName} macro to retrieve the build path in a post-build step:
${workspace_loc:/${ProjName}}/${ConfigName}/${BuildArtifactFileName}
Then you can copy target binaries to your common binary folder, or do something other in the build folder of that particular configuration.
If you open up the project's properties, there is a tab C/C++ Build. This has an option for build location, where you can specify the build directory. It seems you could change this for your multiple projects so that they share the same build directory.
Just happened to be working on something that led me down a similar path - so I'll offer it up as an alternate solution/reminder to myself:
In Eclipse (at least in Luna) the generated makefiles are actually rather decent and convenient. I personally like to create several build configurations (Release and Debug variants with 32 and 64 bit architectures), and supplement them with debug and run (F5 and Execute, respectively) configurations.
To continue: I have been toying with packaging on Debian and found - during the act of said toying - that I needed to create and test an install target. Eclipse neither generates for you, nor provides an interface to - a configuration - for customizing or adding an install target; Other than a place where you can specify that another target exists.
So technically Eclipse does provide an interface; kinda. Hence, I stumbled across the makefile.init, makefile.defs, and makefile.targets files.
Process/Workflow:
Create a file makefile.targets in the root directory of your eclipse project; In said file define an install target manually. This - of course - allows you to specify every little detail as you'd like, but with the added benefit of all of the configuration provided by Eclipse already complete and available to you for use with defining the rules for the specified target.
After defining the new target in the makefile.targets file, right click on your project's name or main cpp file in Eclipse's project explorer, and then select Make Targets->Build..., and finally Add to instantiate a pop-up. Alternatively, you could select 'create' in the last step instead of 'build' and it would provide the same pop-up required for the next part. Add the name of your new target and - leaving everything else at their default values - click ok
If you chose to add the new make target by right-clicking in Project Explorer and selecting Make Target->Build..., after adding the new make target you will be brought back to the first pop-up which resulted from selecting Build.... Otherwise, find your way to the Make Targets->Build.. pop-up now. Select the desired target and then click on Build.
Looking through Eclipse's auto-generated makefiles was an excellent way to learn the makefile syntax and overall structure, and get into some advanced usage of includes and conditionals.
Here are some portions of an example makefile, which - at least I hope - will demonstrate manually setting the output directory of a build:
prefix = /usr/local
bindir = $(prefix)/bin
sharedir = $(prefix)/share
mandir = $(sharedir)/man
man1dir = $(mandir)/man1
...
# Typical all target
all: <binaryname>
#Typical clean target
clean:
rm -f <binaryname> <objectname>.o
# Target invokes all, then installs to specified locations
install: all
install <binaryname> $(DESTDIR)$(bindir)
install -m 0644 <objectname>.1 $(DESTDIR)$(man1dir)