How to install C++11 compiler on Ubuntu? - c++11

I have recently installed Ubuntu 20.04 on my Windows Computer and now want to install C++ 11 compiler on it. I have installed the g++ compiler but now am not able to install or upgrade it ti c++11 compiler. Can someone please tell how to do it?

When you compile use -std=c++11 flag:
g++ -std=c++11 main.cpp
UPD
As per comment below:
-std=c++17 -pedantic

Related

How to configure GNU Autotools to compile a program in 32-bit while on Centos7?

I'm doing all this on a VLE and below is what I'm working with:
Running OS: Linux Centos 7
GCC:4.8.5 & 7.1.0
I'm trying to use GNU autotools (libtool, autoconf, automake) to build a project in 32-bit using gcc-7.1.0. Also, as a requirement, I must do this on Centos 7 and use gcc-7.1.0.
Apparently, the latest version of gcc that can be officially upgraded through yum is 4.8.5. However, I successfully installed gcc-7.1.0 from the official source and even included --enable-multiarch --with-list-multilib=m32,m64 --enable-multilib during configure.
The issue I'm running into is that the autotools seem to want to use the 64-bit libraries even though I'm including -m32 compiler switch in CXXFLAGS, CFLAGS, and LDFLAGS. The reason I think it's using 64-bit libraries at linking is that I get the error below:
libtool: link: g++ -m32 -fPIC -Wall -Wextra -Weffc++ -Werror -std=c++03 -O2 -o fldprog fldprog-icpprog.o ../../ ../seal3/fld/src/.libs/libbsp_fld.a -lpci /usr/local/lib/../lib64/libstdc++.so -lm -Wl,-rpath -Wl,/usr/local/lib /../lib64 -Wl,-rpath -Wl,/usr/local/lib/../lib64
/usr/local/lib/../lib64/libstdc++.so: error adding symbols: File in wrong format
And when I rename /usr/local/lib64 to lib64_something, the program will compile without any errors. However, I want to find a permanent solution.
I've searched the internet for answers but none of them seem to really work. I've tried including -L/usr/local/lib to AM_LDFLAGS, AM_CFLAGS in configure.ac
I'd appreciate any input. Thank you.
Edit:Revised

OpenMP with g++ MacOS on Sierra

I have a makefile with the following that I'm trying to make on macOS Sierra:
CPP = g++
CPPFLAGS = -m64 -fopenmp -O3
and I keep getting the error clang: error: unsupported option '-fopenmp'.
I did
brew install libomp
brew install llvm
brew install gcc
These all were successful but I still get the same error. Would appreciate any suggestions!
There are a number of options...
As you have installed llvm with homebrew, you can compile C++ code using OpenMP with:
/usr/local/Cellar/llvm/9.0.0/bin/clang++ -fopenmp main.cpp -o main
As you have installed GCC with homebrew, you can compile C++ code using OpenMP with:
/usr/local/bin/g++-9 -fopenmp main.cpp -o main
As you have installed libomp, you can use that with the Apple-supplied clang++ (note it is not in /usr/local because it is supplied by Apple) to compile C++ with OpenMP with:
/usr/bin/clang++ -I/usr/local/include -Xpreprocessor -fopenmp -L/usr/local/lib -lomp main.cpp -o main

Mac OSX is using gcc 6.2.0 but g++ 4.9.2

I may not understand this completely, but I thought gcc and g++ were basically the same compiler. I used homebrew to install and link gcc 6.2.0 (see Mac OS X: Installed and linked gcc 6.2 with Homebrew, but gcc --version still says 4.9.2 ).
When I say which gcc I get /usr/local/Cellar/gcc/6.2.0/bin/gcc
When I say which g++ I get /usr/local/bin/g++
Did I miss a step or is my understanding way off?
I had to do this:
cd /usr/local/Cellar/gcc/6.2.0/bin/gcc
ln -s g++-6 g++
which I guess I had previously done for gcc.

Error building ELLCC

Running the build script from ELLCC results in this error
gcc -DHAVE_CONFIG_H -I. -I../../../src/binutils/binutils -I. -I../../../src/binutils/binutils -I../bfd -I../../../src/binutils/binutils/../bfd -I../../../src/binutils/binutils/../include -I./../intl -DLOCALEDIR="\"/Library/Caches/Homebrew/ellcc--svn-HEAD/lib/share/locale\"" -Dbin_dummy_emulation=bin_vanilla_emulation -W -Wall -Wstrict-prototypes -Wmissing-prototypes -Wshadow -Werror -Wno-unused-value -Wno-shadow -MT nm.o -MD -MP -MF .deps/nm.Tpo -c -o nm.o ../../../src/binutils/binutils/nm.c
../../../src/binutils/binutils/nm.c:1690:28: error: 'sbrk' is deprecated
[-Werror,-Wdeprecated-declarations]
char *lim = (char *) sbrk (0);
^
/usr/include/unistd.h:582:7: note: 'sbrk' declared here
void *sbrk(int);
^
The following compilers have been used with the same result:
gcc 4.8
llvm-gcc 2.8
llvm 3.3
I had the same issue compiling binutils-2.24 on Mac OSX Mavericks 13.2.0 with clang. Thanks to Richard Pennington's suggestion, I was able to get binutils to compile by specifying a few other -Wno-error arguments to gcc by setting CFLAGS before running configure. Namely, these are the commands I ran to build and install binutils:
CFLAGS="-Wno-error=deprecated-declarations -Wno-error=unused-variable -Wno-error=unused-function" ./configure --prefix=/usr/local/toolchain-arm-linux-elf --target=arm-linux-elf
make
make install
EDIT: I just noticed that the binutils configure script accepts an --disable-werror argument, which disables gcc turning warnings into errors, and removes the need for the settings CFLAGS. With this argument, building could be done as follows:
./configure --prefix=/usr/local/toolchain-arm-linux-elf --target=arm-linux-elf --disable-werror
make
make install
This error is occurring because sbrk() is deprecated on OSX, -Werror is enabled for the binutils build, and the compiler (in this case "gcc" is an alias for clang) rightly complains about the use of sbrk(). I'll be looking into eliminating this error this weekend when I won't have to be at my day job. ;-)
I looked into it a bit more. This happened because the latest version of OS X (Mavericks) uses clang as its compiler and /usr/include/unistd.h has a deprecated declaration of sbrk().
The solution was to add a -Wno-error=deprecated-declarations option to the CFLAGS for binutils. I also had to make a few other changes to complete the Max OS build. You can find the latest stuff in the ELLCC subversion tree.

How to install PyGSL? (Windows 7, 64 bit, Python 2.7, GSL 1.15)

I'm trying to install PyGSL on my computer (64 bit Windows 7), with Python 2.7 and GSL 1.15 installed. I'm pretty much stuck and I would love for some extra help. GSL installed fine, but its the wrapper that's the problem. For some reason I can't build pygsl. Apparently gcc is the problem (got the same problem on another windows machine). Or it could be that pygsl appears to be using a file named AMD64 while my computer is x86. I would love to use the windows binary for pygsl, but it only exists for python 2.5, and my project needs 2.6 or higher. I've used both the windows binary for GSL and built it from source, but I get the same problem either way. I tried copying dlls from GSL into pygsl but that didn't work. Some forums mentioned a file called gsl.dll but I can't seem to find it. I've also tried to use Cygwin and to compile with minGW32 to no avail.
cmds I ran:
python setup.py install
python setup.py build
python setup.py build_ext -i
python setup.py build --compiler=mingw32
Any ideas?? Thanks.
Cheers,
Bereket
Got the same message in Cygwin as in the windows cmd prompt. Error message:
$ /cygdrive/c/Python27/python.exe setup.py build_ext -i
numpy
Forcing DISTUTILS_USE_SDK=1
Building testing ufuncs!
running build_ext
building 'errno' extension
C compiler: gcc -g -DDEBUG -DMS_WIN64 -mno-cygwin -O0 -Wall -Wstrict-prototypes
compile options: '-DSWIG_COBJECT_TYPES=1 -DGSL_RANGE_CHECK=1 -DDEBUG=1 -DNUMERIC=0 -DPYGSL_GSL_MAJOR_VERSION=1 -DPYGSL_GSL_MINOR_VERSION=15 -UNDEBUG -IC:\Users\Bereket\gsl-1.15\include -IInclude -I. -IC:\Python27\lib\site-packages\numpy\core\include -IC:\Python27\include -IC:\Python27\PC -c'
gcc -g -DDEBUG -DMS_WIN64 -mno-cygwin -O0 -Wall -Wstrict-prototypes -DSWIG_COBJECT_TYPES=1 -DGSL_RANGE_CHECK=1 -DDEBUG=1 -DNUMERIC=0 -DPYGSL_GSL_MAJOR_VERSION=1 -DPYGSL_GSL_MINOR_VERSION=15 -UNDEBUG -IC:\Users\Bereket\gsl-1.15\include -IInclude -I. -IC:\Python27\lib\site-packages\numpy\core\include -IC:\Python27\include -IC:\Python27\PC -c src/init/errorno.c -o build\temp.win-amd64-2.7\Release\src\init\errorno.o
Found executable C:\cygwin\bin\gcc.exe
gcc -g -mno-cygwin -shared build\temp.win-amd64-2.7\Release\src\init\errorno.o -LC:\Users\Bereket\gsl-1.15\lib -LC:\Python27\libs -LC:\Python27\PCbuild\amd64 -lgsl -lgslcblas -lm -lpython27 -lmsvcr90 -o C:\Python27\Lib\pygsl-0.9.5\pygsl\errno.pyd
build\temp.win-amd64-2.7\Release\src\init\errorno.o: In function `add_errno':
/cygdrive/c/Python27/Lib/pygsl-0.9.5/src/init/errorno.c:14: undefined reference to `__imp__PyInt_FromLong'
/cygdrive/c/Python27/Lib/pygsl-0.9.5/src/init/errorno.c:20: undefined reference to `__imp__PyDict_SetItemString'
build\temp.win-amd64-2.7\Release\src\init\errorno.o: In function `initerrno':
/cygdrive/c/Python27/Lib/pygsl-0.9.5/src/init/errorno.c:37: undefined reference to `__imp__Py_InitModule4_64'
/cygdrive/c/Python27/Lib/pygsl-0.9.5/src/init/errorno.c:40: undefined reference to `__imp__PyModule_GetDict'
collect2: ld returned 1 exit status
error: Command "gcc -g -mno-cygwin -shared build\temp.win-amd64-2.7\Release\src\init\errorno.o -LC:\Users\Bereket\gsl-1.15\lib -LC:\Python27\libs -LC:\Python27\PCbuild\amd64 -lgsl -lgslcblas -lm -lpython27 -lmsvcr90 -o C:\Python27\Lib\pygsl-0.9.5\pygsl\errno.pyd" failed with exit status 1
I'm pretty sure now that my GSL install with Cygwin failed / had unresolved dependencies. I'm now trying to install it with visual studio 2010. Here are some good sites for doing that:
Instructions
Alt Method
Installing the Python 2.7 compiler for Windows is a good place to start
http://www.microsoft.com/en-gb/download/details.aspx?id=44266
Running python setup.py build_ext --inplace does the trick for me.
If this doesn't work let me know. You might need to add an environment variable.
Is your Python 32 or 64? To check open Python and do
import sys
sys.versions

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