How CMAKE_ECLIPSE_EXECUTABLE is used? - eclipse

I'm generating Eclipse projects with
cmake -G"Eclipse CDT4 - MinGW Makefiles" path_to_src
In cmake-gui I can see that CMAKE_ECLIPSE_EXECUTABLE is set to CMAKE_ECLIPSE_EXECUTABLE-NOTFOUND
I wonder how CMAKE_ECLIPSE_EXECUTABLE is used by cmake? Is this fine not to set this variable?

I think it is okay not to set it. As far as I now, it is used in newer versions (e.g. see the changes by Alex Neundorf [1]) to retrieve the version of the Eclipse executable. Depending on the version, the project generation is changed.
[1] http://www.kitware.com/blog/home/post/208

Related

Problem with setting up Mingw w64 for C++. Possible conflict with existing Anaconda/Jupyter?

While I am setting up MinGW-W64 (from sourceforge) exe file (for Windows 10) for C++, it shows a message that it was not downloaded correctly. My best guess is that I have a Anaconda/Jupyter setup having MinGW-W64, and it is making all the fuss. How to set it up for both C++ (VS Code / Code lite) and Python/Jupyter/Anaconda?
Make sure you don't mix versions in environment variables like PATH.
Maybe your download was bad?
Or you may have an antivirus software preventing the installation...
You could try a standalone MinGW-w64 build from https://winlibs.com/, which doesn't requite installation - just extract the archive and point VSCode to it.

CMake kits .... are they just for VS Code or would I use them for other environments too?

Background: I work in a company with many preferences. We currently use makefiles for our complex build with the developer's choice of IDE (or even VIM) for editing source files.
I'm looking at CMake to clean up our un-tame-able gnu make build system. I like the integration with VS Code, but I couldn't possibly manage to dictate the IDE to many of our more prickly DSP engineers and their preferred editing environment (which I totally understand; I'm a bit of Visual Studio guy, myself).
Anyways, is the cmake-kits.json method of specifying kits or toolchains/targets/etc. the "right" way to do it? Or is that just for VS Code.
If it's just for VS Code, what's the proper CMake-y way to put in new toolchains (we do cross compiling using non-gnu tools for 3 different processors) that would work in VSCode, or eclipse, or from the command line.
Kits are part of the CMake extension for VS Code. You want to read cmake-toolchains(7). A kit is something like setting CC and CXX in the environment so CMake knows which compiler to use for Makefile and Ninja generators. It is different for the other generators as the IDE can control which exact compiler is used and you tell CMake which toolset to use and it generates the project accordingly. FYI, kits don't handle having to write your own toolchain file for cross compilers.
You can use a toolchain file for cross compiling. This can be simple to hard depending on the compiler and how well it acts like a gcc cross compiler. If it's really different a toolchain file isn't quite enough as you then need to update the platform items to get it all working. Since this gets into the area of being CMake implementation dependent it's not that well documented. But there is help at https://discourse.cmake.org/.
You could just use Ninja as the build tool. Then you setup your toolchain file. After your original run on CMake to create the Ninja project files, you can just run Ninja to build the software.
Then it's easy to set your IDE to just call Ninja to build the software.
Personally, I don't like the CMake integration in VS Code (it's just an add-on). It's always been too buggy for me to want to use it. But it was good for pulling the information out of the build to get the cpp-tools setup correctly. As for project files for Eclipse CDT4 - Ninja I've never personally used them.

How do I find what the Eclipse Cross Settings Prefix should be?

I have installed the latest version of Eclipse on my Windows 7 64-bit machine and the mingw compiler. In setting up a Hello World project, all goes well until I am asked for the Cross Settings what the Prefix is and the Path. The Path is obvious, it's the path to the compiler. However, I haven't the slightest idea what the Prefix is and Googling for much of the day hasn't enlightened me other than finding that a lot of other people have asked the question. Unfortunately the answers I've found appear to be for specific hardware. All I want to do is to produce an executable that will run on a Windows 32 bit or 64 bit machine.
So, what is the Prefix and how do I find what it should be?
What is probably happening here is that CDT is not locating your MingW or GCC installations.
simple - but unlikely reason - covering bases
There can be many reasons, from the simple - but unlikely at this point:
You don't have mingw installed
You don't have GCC installed
This can be tested easily by starting a shell and running gcc --version.
CDT heuristic not working
To more complicated reasons relating to your installation not being detected because the heuristic in CDT did not work on your machine. To find the correct settings, CDT will do:
Check $MINGW_HOME/bin for existence
Check <Eclipse install location>/mingw/bin for existence
Look for mingw32-gcc.exe or x86_64-w64-mingw32-gcc.exe on the PATH
Check C:\MinGW for existence
If CDT cannot find any of the above, you may lead to the situation you are in.
So, how to fix it!
Option 1
Start Eclipse from within a mingw set up shell. i.e. the one you can successfully run gcc --version from. That way Eclipse will inherit an environment that can launch GCC successfully.
Option 2
Set your environment up so that MINGW_HOME is properly defined. You can do this at the system level or within the build settings in Eclipse CDT. For example, on my machine in the build settings for the project (Right-click on the project, choose Properties, then choose C/C++ -> Environment) I have set:
MINGW_HOME to C:\MinGW
MSYS_HOME to C:\MinGW\msys\1.0
PATH to ${MINGW_HOME}\bin;${MSYS_HOME}\bin;<my normal path>
and this allows Eclipse to launch gcc as part of the build process.
NOTE The above setting were done automatically on my machine because mingw was correctly located by the heuristic.
Here is a screenshot of the build settings if it helps:
Prefix: Under the hood
To try and answer part of your original question about what Prefix is, I provide the below information. It is unlikely to be particularly helpf
Prefix, in GCC parlance, refers to the directory under which all the related GCC files are placed. With different prefixes you can have multiple GCC installed on your machine.
From the GCC FAQ:
It may be desirable to install multiple versions of the compiler on
the same system. This can be done by using different prefix paths at
configure time and a few symlinks.
The concept comes from autotools in general. Autotools is the standard GNU make system (where you do ./configure && make - simplified). The prefix is the command line option to the configure stage (--prefix) to specify where to install the tool to. GCC above uses the --prefix to allow multiple GCCs on your system.
If you really want to know more about this, read the autobook. The section on configuring covers --prefix:
‘--prefix=prefix’
The –prefix option is one of the most frequently
used. If generated ‘Makefile’s choose to observe the argument you pass
with this option, it is possible to entirely relocate the
architecture-independent portion of a package when it is installed.
For example, when installing a package like Emacs, the following
command line will cause the Emacs Lisp files to be installed in
‘/opt/gnu/share’:
$ ./configure --prefix=/opt/gnu
It is important to stress that this behavior is dependent on the generated files making use of this
information. For developers writing these files, Automake simplifies
this process a great deal. Automake is introduced in Introducing GNU
Automake.
Additionally, Mingw takes advantage of all this prefix options. Read more about that on mingw's site. But the short of it is that the main prefix for mingw is /mingw.

Eclipse and FFTW

I have some troubles in making a FFTW (and FFTW++) static project in Eclipse in my MacOS Lion. Have someone already made it?
I've made a separate folder for the include files, but it seems like it can't find them despite I have set the path correctly. I've also replaced in all the c-files the includes with the path <subdirectory/include_file> setting in the Directories section of my project settings
${workspace_loc:/FFTW3/include}.
I don't know if it's relevant but as I wrote my code, using another IDE and typing the commands from bash, I realized that some mp options were needed, so I've updated my version of gcc from 4.2.1 (that is the basic Xcode version for MacOS) to 4.7. I've compiled the FFTW++ example and it worked, compiling it with g++ -fopenmp. I have used macports to install the new version of gcc and I have used one of its options (sudo port select --set gcc mp-gcc47) to set it as gcc default command, in place of the 4.2 version, so I can type and compile from bash.
Now I have seen that Eclipse uses the version 4.2.1. Does somebody know how to change it into the 4.7 version? Do you think that this could solve the problem or it's a cause for my problem?

How do you set up an x64 development environment based on gcc and eclipse?

I want to create 64 bit apps for (for example) 64 bit Windows 7. I've searched the web and found some help but couldn't get it to work.
Sorry I've taken so long to respond but I have tried to get the packages suggested to work but they're not easy or else I'm doing something wrong.
Anyway I ran across an environment called pellesc. It consists of a development environment around a compiler which traces is roots back to a 32-bit version that was once (according to Wikipedia) used to develop Quake. From what I've seen so far it's very promising and generates good code too!
In spite of what other people are saying, Eclipse actually has very good support for C++, even in Windows: check out the CDT project. It's very mature and well-supported -- it works for C/C++ at least as well as Eclipse JDT works for Java.
As for the compiler itself, VonC is right, MinGW-w64 (but the mingw-w64 project is moving to mingw-w64.org so i suggest to use mingw-w64.org) is the best option. Eclipse CDT has built-in support for MinGW so as long as you install MinGW first, Eclipse should automatically detect it.
This Eclipse MinGW64 tutorial mentions:
update (Nov 9, 2010): recent MinGW-w64 versions come with 'as', 'g++', and 'gcc' commands. This step may be unnecessary in your MinGW build.
Meaning you won't have anymore to update the GCC assembler, C++ compiler, C compiler and C++ linker, with 'x86_64-w64-mingw32-as', 'x86_64-w64-mingw32-g++', 'x86_64-w64-mingw32-gcc', and 'x86_64-w64-mingw32-g++'.
Other great source for w64 development tools:
Native windows x64 software develop with Mingw-w64 on drangon.org
A 64-bit version of GCC for Windows is available at http://tdm-gcc.tdragon.net/download. I can't see why you would want to use Eclipse for C or C++ programming - try the Code::Blocks IDE at http://www.codeblocks.org instead.
Honestly, I use cygwin. Its compatable with unix so you can easily move systems and has tons of functionality that is gcc friendly (autoconf, make, makedepends, ...). To use gcc to compile to 64 bit add the -m64 option. To compile for windows use the -mno-cygwin option. Make sure though that you're using gcc 3 and not 4 (then you'd use the mingw compiler series). Otherwise, its all the same as unix which is really useful.