Not exactly sure where this question belongs, let me know if I should move it.
Here is the issue; over the past years I have a put together a relatively large personal codebase in C++11 that I'm using for work, but my workplace runs supposedly the latest version of RHEL on their cluster, which runs gcc 4.4.7, which supports C++11 only partially.
I have battled to get a decent compiler installed, but apparently there is no easy way of making this happen, so instead I am wondering whether it would be possible to cross-compile C++11 sources on my own desktop, and export the executable on the cluster at my workplace. I just don't know where to start in order to do that:
Is it possible (and how) to cross-compile C++11 sources from Ubuntu to RHEL?
Since I am at it, is it possible to rebuild gcc 4.8 or a suitable libstdc++ (or libc++) entirely from Ubuntu to an rpm package compatible with RHEL?
(Note: I would preferably use clang (3.4) to compile on my desktop, but gcc (4.8) would be fine too.)
Related
For C++ development on Linux, if I install clang and use it; it actually uses libstdc++(the g++ lib). What's the use of installing the frontend compiler clang on linux then?
I should be good with gcc/g++ only on a linux machine as that's a complete toolchain!
Note: I'm not an expert in C++.
libstdc++ is a default runtime on your Linux. libc++ is not installed by default. If you link your app to libc++, you have to add it as a runtime dependency.
You are right, gcc/g++ is good for Linux, moreover its diagnostic messages are more clear, thus the compiler is better for beginners. By using clang++, you need to know the C++ standard deeper, otherwise it's difficult to get an error reason.
I have a C++ program that uses various C++14 features, and have been asked to compile it for a CentOS 6 system. GCC doesn't support C++14 features on CentOS 6 as far as I can tell (and based on compiler errors).
Is it possible to compile for C++14 on CentOS 6?
Assuming someone has created a whole compatibility layer for compiling C++14 on CentOS6, could I even distribute that executable? Or would the target machine ALSO have to install a compatibility layer?
I recall reading (years ago) about how to use different development toolchains at once, including I think those later than what was supported by the repos for the OS. Just can't recall details.
No, it is not possible to compile C++14 on CentOS 6. Only some C++11 features are available on CentOS 6.
CentOS runs GCC 4.4.7 where-in C++14 features start to become available with GCC 4.9 and higher.
The Boost libraries may be used to replicate some modern C++ features if on an outdated GCC version.
I got my self an ARM based development board (NVIDIA Jetson K1).
The thing is already equipped with Ubuntu system. I was able to use gcc 4.8 directly on the device, but it doesn't contain g++. Installing g++ with apt-get as usual wouldn't work because nobody ever bothered to maintain a complete ppa supporting ARM architecture.
Now I tried to compile the latest GCC manually. Everything went smooth when I compile and installed the requirements (MPC, MPFR, GMP). But I failed building GCC itself, and found out that the mad error in config.log telling me that a working C++ compiler can not be found.
I believe there must be a way to get a working g++ compiler working on the device itself rather than having to cross compile. Does anyone have a clue on how this can be done?
The message is right. GCC 4.8 is written in C++ so it needs to be compiled with a C++ (cross) compiler.
I'm running CentOS 6.4 and need a later version of the C++ compiler to build my development tools (Qt Creator in this case).
I'm unclear on the implications of using devtools and I'm hoping someone can explain.
If I compile programs using devtools, does that means the executable will run on other Centos 6.4 installations without change?
Or..do I know have to ship libraries or other files with my compiled programs?
If so...do I have to modify my C++ code to reference the later libraries? or is this something done by the person installing my compiled program
I hope this somewhat late answer can still help you. What I found is that compiling my project with devtoolset (1.1 in my case, but that should not matter too much) on RHEL 6.4 produces binaries which can almost run on a standard RedHat EL 6.4 (should be similar for Centos 6.4).
The only trouble I ran into was compiling my project with -std=c++11, which produced some problems due to incompatible symbols. The reason is that the GCC folks considered these parts of the standard library to be experimental in GCC 4.4, so they broke ABI compatibility in some places.
Turns out, there's an easy fix: Link your programs with the additional command-line-argument -static-libstdc++. That way, the binary becomes a bit larger but is runs on an unmodified RHEL 6.4 without installing additional libraries/updates for the devtoolset.
To answer your questions explicitly:
Yes, almost.
No.
Don't change the code, just add -static-libstdc++ when linking.
I am new to programming, so have never experienced a language update. With the release of C++11, I want to make use of all the new features such as lambda expressions and threads. I know I can do this with external libraries but using native language features would be more convenient.
I am using gcc 4.2.1 on Mac OS X Snowleopard in Xcode 3.2.6
What all do I need to do and update to start using C++11 features?
You can update to Xcode 4.1 (or whatever the most recent version you can get for Snow Leopard is) and get a new compiler with a few more C++11 features. There are some posts here on Stack Overflow about getting better support for C++11 in Xcode 4.1 on Snow Leopard.
But even the latest compiler available through Xcode does not support some C++11 features like lambdas. To get the best C++11 support you'll want to install a newer compiler, gcc 4.6 or 4.7, or Clang.
I frequently build the latest version of clang from source. It's not difficult to do if you're familiar with building other open source software. I use the git repos for clang and llvm, http://llvm.org/git/llvm.git and http://llvm.org/git/clang.git. You can also find instructions on their website for getting started: http://clang.llvm.org/get_started.html. Once you have the source for clang and llvm it's just ./configure && make && sudo make install. (you might want to run the tests before installing, since this is directly out of the repository. After make do make check in the llvm directory, and once that passes cd down to tools/clang and run make test. If everything is okay then sudo make install)
I don't remember if Snow Leopard included libc++ or not, so you may need to get that as well. http://libcxx.llvm.org/
Once everything is built and installed you can do:
clang++ -std=c++11 -stdlib=libc++ main.cpp && ./a.out
and you should have just about the best C++11 support around.
Recent patches in clang have really improved support for the last features you're likely to notice as a new C++ programmer. There are still a few bits and pieces left, but as of 3.1, and as far as I'm aware, clang has every C++11 feature that either gcc 4.7 or VC++11 has and more besides. libc++ also has the fewest gaps in terms of C++11 standard library features IME (though I think VC++'s standard library will also be pretty complete once they catch up on language features, e.g. char32_t and char16_t as native types so that the standard's mandated specializations for those types can be used).
Basically you only need to get a toolchain that has support for the new features. In macosx that would be either GCC or clang++. You might need to download/compile a particular version if needed (i.e. if the feature that you want to try is not in a prepacked compiler bundle but is available in the repository).
I downloaded and compiled the latest trunk of clang++ from subversion to do some testing, and installed g++ 4.6 with macports in Snow Leopard. I remember that I had some issues with the setup of the environment, but don't quite remember which of the compilers gave me problems or how I solved them. Google is your friend there :)
If you have homebrew installed, from this article, just two steps:
brew tap homebrew/dupes
brew install gcc --enable-cxx --enable-fortran --use-llvm