I have been using Eclipse for the past two years for an embedded linux project.
I am able to run my code on Unbutu host unchanged and as such do most of my testing
on the host. Each project has a Debug configuration for host and Target-Debug for
embedded linux device that builds with cross compile toolchain.
My workspace has more than 20 projects which consist of libraries and executables that
reference the libraries. The problem I have is that anytime I build an executable there seems to no rhyme or reason to the way eclipse rebuilds the referenced libraries. It will nearly always build several of them when no changes to any of the code in the libraries has changed. When it builds the libraries it builds all of the source in them, not just a few files. In some cases it will do so even when the target executable is up to date and not itself rebuilt. I can clean the executable, then build. Right away do another build and instead of reporting everything is up to date it might still build some of the libraries. Build another time and it might build the same libraries again or in some cases finally report that everything is up to date.
Every build configuration for an executable has the exact library build referenced as opposed to "active". For example for a Target-Debug executable build configuration I reference the Target-Debug build of the libraries it depends on. When I build executables it is often possible that the "active" build configuration selected for libraries are not the same as executable I'm building but that shouldn't matter if the build configuration for the executable references specific library build configurations.
At one time the problem included rebuilding configurations that weren't even of the same
type. That is, building a Debug version of executable would also cause Target-Debug configurations of libraries to be rebuild also. That problem seem to be resolved by unchecking Project References (as opposed to C/C++ General/Paths and Symbols/References).
I experienced this same problem with Helios, Juno and now Kepler with respective CDT releases.
How can I prevent eclipse from re-building dependent library projects when they haven't changed? I have tried everything to figure out why it's happening and search for solutions. Maybe some misunderstanding on my part of some concept in eclipse build? I'm at a loss...
Any advice would be greatly appreciated.
Related
My advance appologies for being hopeless at Windows development. I am by no means a Windows developer and my understanding of how to write, compile and link C++ code on a Windows system is limited to say the least.
I am having difficulty trying to compile and link a SFML project on a Windows 10 system with the CodeBlocks IDE.
I am trying to link this project with static linking, not dynamic linking. Again I have virtually no idea how the two different methods work in detail, I just know that if I ship a static linked binary to another Windows 10 user it is much more likely to "just work" on their system.
List of things I did:
Downloaded the latest version of CodeBlocks with MINGW integration.
Installed, default options
Downloaded the latest version of SFML (32bit MINGW version)
Extracted the zip file (SFML) to my home directory
Created a new codeblocks project (console application) and followed the instructions to set the compiler and linker options
https://www.sfml-dev.org/tutorials/2.5/start-cb.php
It works fine for dynamic linking, but requires me to copy the .dll files to the same dir as the produced executable file (produced from compilation of my C++ code).
I tried to change to static linking, changing the names of the linker libs with the -s or -s-d suffix, and adding the define SMFL_STATIC option to global (release and debug) options. I also added the opengl32, freetype, winmm and gdi32 link libs, before their respective sfml link libs.
When trying to compile I get the following linker errors
cannot find -lfreetype
cannot find -lsfml-graphics-s-d
cannot find -lsfml-window-s-d
cannot find -lsfml-system-s-d
in Release mode, similar errors are produced.
What am I doing wrong?
My hunch would be that you either have the wrong compiler (see below) or you haven't defined the library directory as mentioned in the linked tutorial.
There are four common things to consider when using SFML (and essentially any other C++ library) on Windows.
Compiler versions have to fully match
Make sure to not mix x86 and x64
Settings need to be specified for the correct configuration
When linking libraries statically, you also need to link the dependencies
Compiler versions have to fully match
Since C++ doesn't have a standardized ABI, the generated libraries will never be reusable between compilers. Yes, sometimes "it works", but it can break at any point and there's no guarantee.
We strongly recommend to either use the compilers linked on the SFML Download page or build SFML from source with your current compiler.
If you got the latest stable Code::Blocks version with MinGW as stated, you should also be able to get a snapshot build of SFML, which should be using the same compiler.
Note: One exception to this rule is Visual Studio, where VS 2017 binaries are compatible with VS 2019 (and maybe VS 2022?).
Make sure to not mix x86 and x64
When you download a 32-bits (x86) version of SFML, you also need a 32-bits version of your compiler. When you download a 64-bits (x64) version of SFML, you also need a 64-bits version of your compiler.
Make sure you double check your compiler configuration that you've selected the correct bit-ness.
Note: For Visual Studio you need to select the correct compiler architecture in the IDE, usually positioned right next to the run button.
Settings need to be specified for the correct configuration
Project configurations are usually spread across the matrix built from the types:
Debug / Release / All
x86 / x64 (for VS)
Make sure when you add the settings for library paths and include paths that it's not just set for debug or release and ends up missing in either or the other configuration.
Also make sure you're not setting up debug libraries (with the -d suffix) in release mode or release libraries (without any suffix) in debug mode.
When linking libraries statically, you also need to link the dependencies
The SFML static libraries don't contain any symbols of any of its dependencies, that means, in your final application you have to link static SFML and all its dependencies.
As a short summary you can think of static libraries like an archive of object files. These object files will directly be linking into your application, like you link your own source file object files. As such, the SFML static libraries only contain object files of SFML itself and not of other libraries as well.
Troubleshooting
If nothing seems to help, then you should enable verbose compiler & linker output, that we you see exactly which commands are invoked and one can quickly spot the missing statements.
In a project I am working on I depend on a couple of external libraries that are necessary for the program to run. On my local machine they can be found in usr/local/lib and everything works like a charm.
Now, when I build my Release I want these libraries to be added to the build
(I want to end up with my executable and all necessary libs) and configure it, such that when I run the program from commandline, it knows the libraries are in lib.
I could manually add all the libraries in this folder on my local machine and configure my project so that it can find the libraries here, but, even using variables, it still inserts a local path, so using it on other machines does not work. Or is there a way to do this starting from the project path?
Is this possible using CDT?
If you use relative paths to the project folder, that should be totally portable, as long as the other machines can run such libraries. For example if your project is in /home/Fristi/project, you could just copy all your static libraries into ./libs (which actually points to /home/Fristi/project/libs and add ./libs in your makefile or CDT configuration.
I'm having my first fling with the Boost libraries, and I've picked a pretty girl named Regex.
I've installed the libraries (which build automatically?) on my machine, but I'm getting the above error (cannot find -lboost_regex). I'm using Code::Blocks with MinGW, and a C++0X compiler flag.
I have
Pointed the "search directories" to the installation directory
Added the -lboost_regex flag to the linker
but no luck. Can someone help me get this working?
Update
Got things running now. I've added some further notes in an answer below, for newcomers to this problem.
(Also, changed the title of the question since it turned out to be a broader issue than when I started out.)
Here's some links and tips that can help a newcomer, from my first build experience. I built the libraries directly from the zip file. I built on MinGW and I used CodeBlocks for the IDE.
Download Boost zip, unzip somewhere (I'll call that place $boostdir)
Pretty large when unzipped, > 300MB
Add MinGW bin to PATH var
When Boost builds, it will need access to MinGW executables
Build b2.exe and bjam.exe
The documentation for Windows blithely assumes MSVC compiler is available.
If it is, you can apparently use the bootstrap.bat like the docs say.
If it's not (like mine), you'll have to build the exe files yourself, in steps 4 and 5.
In CMD, navigate to $boostdir/tools/build/v2/engine
Run build.bat mingw (will build b2.exe and bjam.exe)
Some aging basic documentation on that
Now you've got b2 and bjam custom-built according to your system spec. Navigate back up to $boostdir and get ready to start building the libraries.
Boost will make a new bin.v2 directory in the current directory.
All the libs will go in bin.v2.
This is an "intermediate" directory, for some reason
Nothing to do in this step, just some extra info :)
Run b2 toolset=gcc --build-type=complete
This takes a long time, in the neighborhood of 1 - 2 hours.
You'll know if it's working. If you think something's wrong, it's not working.
The build can use various flags
Now you're all built. Time to set up CodeBlocks.
Point your compiler to the header files
Right click your project -> Build Options -> Search Directories tab -> Compiler tab -> add $boostdir address
Boost has built a DLL for the library you want according to your current system spec. Look in the stage\lib\ directory of $boostdir
This DLL will be used later in the linker, so don't close its explorer window yet
Mine was in C:\Program Files\Boost_1_52\stage\lib\libboost_regex-mgw44-1_52.dll
I think the documentation had a smart way to do this but I haven't tried it yet
The "intermediate" directory from step #6 can be deleted now that the build is finished
Point your linker to the directory of that DLL
Right click your project -> Build Options -> Search Directories tab -> Linker tab -> add
that directory address (blah\blah\blah\stage\lib\)
Add that DLL flag to your linker settings
Mine was -lboost_regex-mgw44-1_52
Deep breath, prayers to your god, and fire up a test.
Further docs that may either help or confuse:
The Code::Blocks website has a version of this that I didn't find until I neared the end of my search. It was fairly helpful but had a few weird things. This post also is helpful.
Good luck!
I'm not sure what you mean by which build automatically. Most of the Boost libraries are header-only, but a few, such as regex, need to be compiled to a shared / static library. The compilation step is not automatic, you need to invoke the Boost build system (bjam) to do this. Of course, there are sources (BoostPro for instance) that distribute pre-built Boost binaries for various platforms.
Once that's done, you need to add the path where the libraries are present to the linker's search path. For MinGW, this option is -L"path/to/library". Boost does have directives to allow auto-linking of the required libraries, and this seems to work pretty well with MSVC, but I've never gotten it to work with MinGW. So you must also list the libraries to be linked explicitly. The Boost libraries include target and version information in the file name by default, so a typical linker command line option will look like -lboost_regex-mgw47-mt-1_51 for MinGW gcc 4.7 and Boost 1.51
According to this answer, the intended way to include non-header-only parts of Boost into a Visual Studio 2010 project require the use of bjam to build the correct libraries.
What is unclear to me is whether this is a one-time-only thing, where I just check in the lib files produced by bjam, or whether anyone who wants to build my project will from now on require not only Visual Studio but also bjam.
The project only targets Windows 32-bits, because it builds a plugin for a program that's only available in this configuration, and only needs to support the statically-linked multi-threaded CRT.
(For the record, if I just include the relevant .cpp files into the build, the compile stage succeeds, but at link stage I get a missing library error, which is apparently caused by the "auto-link" feature. Perhaps I should just disable auto-linking, if it's possible?)
You don't need bjam. Like yasouser answered, you can download the installer from boost pro, the downsides being that
you need to register though that's quick and easy
it's usually/sometimes a release or two behind the latest boost release.
What is unclear to me is whether this is a one-time-only thing, where I just check in the lib files produced by bjam, or whether anyone who wants to build my project will from now on require not only Visual Studio but also bjam.
It is a one time thing per machine. Once you have the boost binaries you don't need bjam anymore. The nice thing about the installer is that you can install some selected versions of the boost libraries + the headers (You can select VS version, single-threaded, static/dynamic, etc. on a per library basis e.g. thread, system, etc.) and then at a later point you can just run the installer again and add other binaries.
So if you're auto-linking and are missing a specific lib, just run the installer again.
FYI, you can disable boost's autolinking option by defining BOOST_ALL_NO_LIB and then manually linking in the lib versions you want.
Some of the boost libraries require you to build them as static or shared libraries and link them in your project. Either you can download the source and build it for yourself using bjam or you can install the pre-built binaries from here.
Yes this is a one time install (if you are installing from pre-built binaries or built by yourself). And those building your project will also need to do the boost install once for them to be able to build your project.
if I just include the relevant .cpp
files into the build
Direct including cpp files has many drawbacks. The only reason of borrowing .cpp files I can imagine is to allow build the project on other PCs without installing boost there. But I think it can be solved by distributing particular boost .lib files as well.
My development shop has put together a fairly useful Python-based test suite, and we'd like to test some Linux-based C++ code with it. We've gotten the test project they ship with Boost to compile (type 'bjam' in the directory and it works), but we're having issues with our actual project.
Building the boost libraries and bjam from source (v1.35.0), when I run bjam I get a .so in the bin/gcc-4.1.2/debug directory. I run python and "import " and I get:
ImportError: libboost_python-gcc41-d-1_35.so.1.35.0: cannot open shared object file: No such file or directory
Looking in the library directory, I have the following:
libboost_python-gcc41-mt-1_35.so libboost_python-gcc41-mt-1_35.so.1.35.0 libboost_python-gcc41-mt.so
Obviously I need the -d instead of the -mt libraries, or to point at the -mt libraries instead of -d, but I can't figure out how to make my Jamroot file do that.
When I install Debian Etch's versions of the libraries, I get "No Jamfile in /usr/include" - and there's a debian bug that says they left out the system-level jamfile.
I'm more hopeful about getting it working from source, so if anyone has any suggestions to resolve the library issues, I'd like to hear them.
Response to answer 1: Thanks for the tip. So, do you know how I'd go about getting it to use the MT libraries instead? It appears to be more of a problem with bjam or the Jamfile I am using thinking I am in debug mode, even though I can't find any flags for that. While I know how to include specific libraries in a call to GCC, I don't see a way to configure that from the Boost end.
If you want to build the debug variants of the boost libraries as well, you have to invoke bjam with the option --build-type=complete.
On Debian, you get the debug Python interpreter in the python2.x-dbg packages. Debug builds of the Boost libraries are in libboost1.xy-dbg, if you want to use the system Boost.
Found the solution! Boost builds a debug build by default. Typing "bjam release" builds the release configuration. (This isn't listed in any documentation anywhere, as far as I can tell.) Note that this is not the same as changing your build-type to release, as that doesn't build a release configuration. Doing a 'complete' build as Torsten suggests also does not stop it from building only a debug version.
It's also worth noting that the -d libraries were in <boost-version>/bin.v2/libs/python/build/<gcc version>/debug/ and the release libraries were in <gcc-version>/release, and not installed into the top-level 'libs' directory.
Thanks for the other suggestions!
One important Point: -d means debug of course, and should only be linked to a debug build of your project and can only be used with a debug build of python (OR NOT, SEE BELOW). If you try to link a debug lib to a non-debug build, or you try to import a debug pyd into a non-debug python, bad things will happen.
mt means multi-threaded and is orthogonal to d. You probably want to use a mt non-d for your project.
I am afraid I don't know how to tell gcc what to link against (I have been using Visual Studio). One thing to try:
man gcc
Somewhere that should tell you how to force specific libs on the linker.
EDIT: Actually you can import a debug version of you project into a non-debug build of python. Wherever you included python.h, include boost/python/detail/wrap_python.hpp instead.