OpenMP with g++ MacOS on Sierra - gcc

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

Related

libgomp and MacOsx

I am using MacOS Mojave version 10.14.16 and I am trying to install http://www.rpl2.net/index.php (a programming language using Reverse Polish Notation as found on some HP calculators like the 48GX), supposed to work on MacOSX (they say "MacOS X (Xcode 3.1.4 + gfortran 4.5)").
So I have downloaded the latest stable release, cd to the folder, and wanted to run
./configure
make
make install
But the ./configure is failing due to "configure: error: Can not find libgomp !". There is no libgomp package I can install with brew (I already installed gcc which comes with gfortran and thought it would provide libgomp but apparently not).
Could someone help a poor applied mathematician trying to install a software on its macbook?
Thanks
EDIT
in my config.log I have this, maybe it will help:
configure:7433: checking for vim
configure:7449: found /usr/bin/vim
configure:7461: result: yes
configure:7507: checking for main in -lm
configure:7526: gcc -o conftest -g -O2 -O2 -fno-strict-overflow conftest.c -lm >&5
configure:7526: $? = 0
configure:7535: result: yes
configure:7548: checking for pthread_mutex_init in -lc
configure:7573: gcc -o conftest -g -O2 -O2 -fno-strict-overflow conftest.c -lc -lm >&5
configure:7573: $? = 0
configure:7582: result: yes
configure:7687: checking for omp_get_num_procs in -lgomp
configure:7712: gcc -o conftest -g -O2 -O2 -fno-strict-overflow conftest.c -lgomp -lc -lm >&5
ld: library not found for -lgomp
clang: error: linker command failed with exit code 1 (use -v to see invocation)
configure:7712: $? = 1
You don't say how you installed GCC. If you did it using homebrew, and
brew install gcc
you should be able to see:
/usr/local/Cellar/gcc/10.2.0/lib/gcc/10/libgomp.dylib
which would mean you need to compile with:
gcc ... -L /usr/local/Cellar/gcc/10.2.0/lib/gcc/10 -l gomp ...
Failing that, you can always search for libgomp with:
find /usr -name "lib*gomp*lib"
You can test which gcc you are using with:
type gcc

gcc compile, getting "clang: error: unsupported option '-fopenmp'"

I am running the command
gcc -o openmptest -fopenmp openmptest.c
however am getting the error:
clang: error: unsupported option '-fopenmp'
I am running this on Mac Mojave. In addition I am using VS code which is telling me
cannot open source file "omp.h"
for my include statement.
I think it could work if you install libomp by
brew install libomp
and then,
clang -Xpreprocessor -fopenmp -I/usr/local/include -L/usr/local/lib -lomp openmptest.c -o main
This should work, I was having the same issue and and managed to compile my code by using the above.

Install xgboost on Mac - ld: library not found

I am trying to install OpenMP enabled xgboost on my mac. I installed gcc with no problem:
brew install gcc --without-multilib
then cloned git repository:
git clone --recursive https://github.com/dmlc/xgboost
cd xgboost; cp make/config.mk ./config.mk
but I get an error when I do
make -j4
Here is the error I get. I'd appreciate if you can help fixing this problem:
c++ -std=c++0x -Wall -O3 -msse2 -Wno-unknown-pragmas -funroll-loops -Iinclude -Idmlc-core/include -Irabit/include -fPIC -fopenmp -o xgboost build/cli_main.o build/learner.o build/logging.o build/c_api/c_api.o build/c_api/c_api_error.o build/common/common.o build/data/data.o build/data/simple_csr_source.o build/data/simple_dmatrix.o build/data/sparse_page_dmatrix.o build/data/sparse_page_raw_format.o build/data/sparse_page_source.o build/data/sparse_page_writer.o build/gbm/gblinear.o build/gbm/gbm.o build/gbm/gbtree.o build/metric/elementwise_metric.o build/metric/metric.o build/metric/multiclass_metric.o build/metric/rank_metric.o build/objective/multiclass_obj.o build/objective/objective.o build/objective/rank_obj.o build/objective/regression_obj.o build/tree/tree_model.o build/tree/tree_updater.o build/tree/updater_colmaker.o build/tree/updater_histmaker.o build/tree/updater_prune.o build/tree/updater_refresh.o build/tree/updater_skmaker.o build/tree/updater_sync.o dmlc-core/libdmlc.a rabit/lib/librabit.a -pthread -lm -fopenmp
c++ -std=c++0x -Wall -O3 -msse2 -Wno-unknown-pragmas -funroll-loops -Iinclude -Idmlc-core/include -Irabit/include -fPIC -fopenmp -shared -o lib/libxgboost.so build/learner.o build/logging.o build/c_api/c_api.o build/c_api/c_api_error.o build/common/common.o build/data/data.o build/data/simple_csr_source.o build/data/simple_dmatrix.o build/data/sparse_page_dmatrix.o build/data/sparse_page_raw_format.o build/data/sparse_page_source.o build/data/sparse_page_writer.o build/gbm/gblinear.o build/gbm/gbm.o build/gbm/gbtree.o build/metric/elementwise_metric.o build/metric/metric.o build/metric/multiclass_metric.o build/metric/rank_metric.o build/objective/multiclass_obj.o build/objective/objective.o build/objective/rank_obj.o build/objective/regression_obj.o build/tree/tree_model.o build/tree/tree_updater.o build/tree/updater_colmaker.o build/tree/updater_histmaker.o build/tree/updater_prune.o build/tree/updater_refresh.o build/tree/updater_skmaker.o build/tree/updater_sync.o dmlc-core/libdmlc.a rabit/lib/librabit.a -pthread -lm -fopenmp
clangclang: : warningwarning: : argument unused during compilation: '-pthread'argument unused during compilation: '-pthread'
ld: library not found for -lgomp
ld: library not found for -lgomp
clang: error: clanglinker command failed with exit code 1 (use -v to see invocation):
error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [lib/libxgboost.so] Error 1
make: *** Waiting for unfinished jobs....
make: *** [xgboost] Error 1
I have the same issue and solved it by:
brew install clang-omp
export CC=clang-omp
export CXX=clang-omp++
git clone --recursive https://github.com/dmlc/xgboost
cd xgboost; cp make/config.mk ./config.mk; make -j4
cd python-package
sudo python setup.py install
If you used pip to install xgboost before, then delete the previous installed xgboost from your project. Then use
pip install xgboost
to install it again.
A new versions of OSX has a Clang as a default c\c++ compiler. Therefore your c++ command refers to clang++.
You should define a CC\CXX environmental variables for your make command like this CC=gcc CXX=g++ make -j
Also you can build an OpenMP for clang OpenMPrt and customise your shell environment (I didn't try this by own)
(I have no mac at this moment to check this solution; just linux)

Clang boost header not found

I am trying to compile a Python PCL module which builds some C++ source. I am getting this error:
$ python setup.py install
running install
running build
running build_py
running build_ext
skipping 'pcl/_pcl.cpp' Cython extension (up-to-date)
building 'pcl._pcl' extension
/usr/bin/clang -fno-strict-aliasing -fno-common -dynamic -g -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -I/Library/Python/2.7/site-packages/numpy/core/include -I/usr/local/Cellar/pcl/HEAD/include/pcl-1.8 -I/usr/local/Cellar/eigen/3.2.3/include/eigen3 -I/usr/local/Cellar/pcl/HEAD/include/pcl-1.8 -I/usr/local/Cellar/flann/1.8.4/include -I/usr/local/Cellar/pcl/HEAD/include/pcl-1.8 -I/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c pcl/_pcl.cpp -o build/temp.macosx-10.6-intel-2.7/pcl/_pcl.o
pcl/_pcl.cpp:244:10: fatal error: 'boost/smart_ptr/shared_ptr.hpp' file not
found
#include "boost/smart_ptr/shared_ptr.hpp"
^
1 error generated.
error: command '/usr/bin/clang'
For whatever reason clang isn't looking in /usr/local/include where it most definitely would find the boost headers. As you can see it is linking all the other dependencies fine. What can I add that so clang will find boost?
On OSX 10.10, nothing fancy happening anywhere. Boost was probably installed by homebrew, but the files are all in /usr/local/include/boost as I'd expect.
Check the output of /usr/bin/clang++ -v some_test_file.cpp but chances are /usr/local/include isn't in the standard search path of the compiler.
You'll need to add -I/usr/local/include to CXXFLAGS or CPPFLAGS or whatever appropriate place in your build script or environment. It seems the python build script is failing to properly detect Boost.
If the above is not true (and /usr/local/include does show up in the output), make sure /usr/local/include/boost/smart_ptr/shared_ptr.hpp exists.

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.

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