How can I properly configure the g++ include path with mingw64? - g++

I have installed msys2/mingw64 because I need the g++ compiler. Now, I want to compile some c++ oce which requires openblas. I have installed the package using pacman -S mingw-w64-x86_64-openblas. However, compiling the code fails with
fatal error: cblas.h: No such file or directory
Clearly, the include path does not contain the headers from openblas which are located at C:\msys64\mings64\include\openblas. This is easy to fix by passing -I<include path> as an additional argument to g++.
Now, I was wondering whether there is an automated way to include include files/headers of installed packages in the g++ include path. The same problem also holds for libraries.
For example, pacman might be able to atomatically append these paths onto some environment variable which g++ checks.

The standard way to get compilation and linking options for a library on MSYS2 and other Unix-like systems is to run this command:
pkg-config --cflags --libs openblas
If you're just compiling, use --cflags by itself.
If you're just linking, use --libs by itself.
Here's an example Bash command you could use to compile a single-file program:
g++ foo.cpp $(pkg-config --cflags --libs openblas) -o foo

Related

CMake : Selecting mpich over openmpi

I am using cmake 3.10.2. I have both openmpi and mpich installed. However I need to load only mpich. So I found from the documentation the following
MPI_EXECUTABLE_SUFFIX
A suffix which is appended to all names that are being looked for.
For instance you may set this to .mpich or .openmpi to prefer the one
or the other on Debian and its derivatives.
My CMake file goes like this
set(MPI_EXECUTABLE_SUFFIX ".mpich")
FIND_PACKAGE(MPI REQUIRED)
INCLUDE_DIRECTORIES(${MPI_INCLUDE_DIRS})
LINK_DIRECTORIES(${MPI_LIBRARY_DIRS})
message(${MPI_INCLUDE_PATH})
However this shows
/usr/lib/x86_64-linux-gnu/openmpi/include/openmpi/usr/lib/x86_64-linux-gnu/openmpi/include...
Where am I going wrong. Could you please help me with this
Also
mpicc -show
gcc -I/usr/lib/x86_64-linux-gnu/openmpi/include/openmpi -I/usr/lib/x86_64-linux-gnu/openmpi/include/openmpi/opal/mca/event/libevent2022/libevent -I/usr/lib/x86_64-linux-gnu/openmpi/include/openmpi/opal/mca/event/libevent2022/libevent/include -I/usr/lib/x86_64-linux-gnu/openmpi/include -pthread -L/usr//lib -L/usr/lib/x86_64-linux-gnu/openmpi/lib -lmpi
mpicc.mpich -show
gcc -Wl,-Bsymbolic-functions -Wl,-z,relro -I/usr/include/mpich -L/usr/lib/x86_64-linux-gnu -lmpich
the best is to use modules for switch between openmpi and mpich:
$ module load mpich
$ module unload mpich
$ module load openmpi
http://modules.sourceforge.net/
The default mpicc is not your choice. You can specify it manually in the cmake file, or update the $PATH variable with your mpicc included before the default one. Personally, I installed the mpich in the /usr/local/ directory.
Regards

Error when linking GSL with -static

I have written a programm in c++. Linking and runiing is working, as long as I don't use the "-static" option for g++. But I have to run it from an Antergos USB-Live Stick with default settings and there is no GSL included. In the manual of GSL they recommend
$ g++ -c main.cpp
$ g++ -static main.o -lgsl -lgslcblas -lm -lnlopt
But for this code I receive an error message:
/usr/bin/ld: cannot find -lgsl
/usr/bin/ld: cannot find -lgslcblas
collect2: Fehler: ld gab 1 als End-Status zurück
I tried it as this question, but it didn't work for me. When I run
$ g++ -O2 -o test main.cpp -lgsl -lgslcblas -lnlopt -lm
$ lld test
it prints
linux-vdso.so.1 (0x00007fffa5b95000)
libgsl.so.19 => /usr/lib/libgsl.so.19 (0x00007f8748c9a000)
libgslcblas.so.0 => /usr/lib/libgslcblas.so.0 (0x00007f8748a5d000)
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007f87486d5000)
libm.so.6 => /usr/lib/libm.so.6 (0x00007f87483d1000)
libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007f87481ba000)
libc.so.6 => /usr/lib/libc.so.6 (0x00007f8747e1c000)
/lib64/ld-linux-x86-64.so.2 (0x00007f87490fe000)
So I tried to create a symlink, but I do have also "libgsl.so"
$ ls /usr/lib/libgsl
libgslcblas.so libgslcblas.so.0.0.0 libgsl.so.19
libgslcblas.so.0 libgsl.so libgsl.so.19.3.0
Am I doing something stupid? Thank your for your help.
When you pass -lgsl, by default you request the linker to
find and link either the shared library libgsl.so or the static
library libgsl.a and to prefer the shared library, if both are found
in the same search directory. The linker will search, first, in any
directories you have specified with the -L/path/to/search options,
in the order you specified, and then in its default search directories
(/usr/lib, etc.). Likewise for -lgslcblas.
But when you pass the linkage option -static to gcc/g++, it prevents
linking with any shared libraries. Shared libraries, libgsl.so, libgslcblas.so
will be ignored. Static libraries libgsl.a, libgslblas.a, must be
found, in some or other of the search directories, for the linkage to
succeed.
The linker is saying:
/usr/bin/ld: cannot find -lgsl
/usr/bin/ld: cannot find -lgslcblas
because it can't find those static libraries - presumably because you
haven't installed them.
You do not say what linux distro you are working on, but if the package
that provides libgsl and libgslcblas is called, say, libgsl[suffix]
then there will be a corresponding package called libgsl-dev, libgsl-devel,
or similar. This will be the development version of the package,
for the use of people who want to develop software that links with libgsl
or libgslcblas. The development package will require the libgsl package as a dependency
- so it will install the same stuff - and will in addition contain the
library's header files and the static version of the library.
So you need to install the libgsl development package for your distro.
For Ubuntu, for example, that is libgsl-dev:
Later
I gather that your distro, Arch Linux, does not do separate dev packages. You
need to build the static libraries from source. To do that you will need
at least to have installed:
GNU Make
GNU autotools (autoconf, automake, libtool)
GCC (C compiler)
texinfo
Then to make a default build:
Get the gsl source package from https://savannah.gnu.org/git/?group=gsl
either by cloning the git repo or downloading a current tar.gz tarball
and extracting it.
cd into the package directory.
run ./autogen.sh. This will succeed provided the GNU autotools prerequisites
are fulfilled.
run ./configure --enable-maintainer-mode (as ./autogen.sh will have prompted you).
This will succeed provided that the package dependencies are satisfied
and environment sanity checks pass.
run make
If make completes without errors - which will take a matter of minutes -
then, as root, run make install.
If all is well, this will install your missing static libraries:
/usr/local/lib/libgsl.a
/usr/local/lib/libgslcblas.a
You should not need to modify your linkage command for the linker to find
them: /usr/local/lib is a default linker search path.

Set multiple paths to CMAKE_Fortran_MODULE_DIRECTORY

So I am trying to include an installed Fortran library to a CMake project. I know the directory where the module (.mod) file is located, but my project can't seem to find it unless I set CMAKE_Fortran_MODULE_DIRECTORY.
SET(LIB_INCLUDE_DIR /usr/local/include)
SET(EX_FILES main.f90 file1.f90 file2.f90)
INCLUDE_DIRECTORIES(${LIB_INCLUDE_DIR})
ADD_EXECUTABLE(test ${EX_FILES})
TARGET_LINK_LIBRARIES(test lib1)
Where the error is
use lib1
1
Fatal Error: Can't open module file 'lib1.mod' for reading at (1): No such file or directory
unless I include the line
SET(CMAKE_Fortran_MODULE_DIRECTORY ${LIB_INCLUDE_DIR})
And then it can find the file just fine. But I'm running into a little problem. By setting CMAKE_Fortran_MODULE_DIRECTORY, CMake tries to write all generated modules to this directory rather than the CMAKE_BINARY_DIR (where I would like it).
From the documentation, I know that CMAKE_Fortan_MODULE_DIRECTORY is meant to be set to specify where to write generated module files, but some compilers look to that directory to find modules. Is there any way to set multiple directories so that if it can't find in/write to one directory, it searches the second? When I try to set CMAKE_Fortran_MODULE_DIRECTORY to be multiple directories, it only looks at the first directory.
If it helps I am on a Ubuntu 14.04 LTS system using gfortran 4.8.4
EDIT:
So by Alexander Vogt's suggestion I ran with VERBOSE=1 and got
cd /home/user/Repos/build/src && gfortran -I/home/user/Repos/build/src -isystem /usr/local/include -c /home/user/Repos/test_project/src/main.f90 -o CMakeFiles/test.dir/main.f90.o
when I did NOT set CMAKE_Fortran_MODULE_DIRECTORY and
cd /home/user/Repos/build/src && gfortran -J/usr/local/include -I/home/user/Repos/build/src -isystem /usr/local/include -c /home/user/Repos/test_project/src/main.f90 -o CMakeFiles/test.dir/main.f90.o
when I did.
It seems the only difference is the -J flag, which sets exactly what CMAKE_Fortran_MODULE_DIRECTORY sets. Is there some flag that sets just where to look for compiled modules, and not where to put them?

Using libdl.so in MinGW

I want to generate a dll file in MinGW, I have several object dependencies in order to do that, one of my object dependencies is libdl.so, I add this object in unix simply as :
g++ xx.o yy.o /usr/lib/libdl.so -o module.so
but in MinGW, I don't have any idea how to add this object. any ideas?
There is a MinGW port of libdl that you can use just like under Unix. Quote from the website:
This library implements a wrapper for dlfcn, as specified in POSIX and SUS, around the dynamic link library functions found in the Windows API.
It requires MinGW to build.
You may get pre-built binaries (with MinGW gcc 3.4.5) and a bundled source code from the Downloads section.
The following commands build and install it in a standard MinGW installation (to be run from your MinGW shell):
./configure --prefix=/ --libdir=/lib --incdir=/include && make && make install
To compile your library as a DLL, use the following command:
g++ -shared xx.o yy.o -ldl -o module.dll
I encountered the same problem (msys2, 32bit version of compiler etc.).
For me I found out that the libdl.a was available in /usr/lib but not in /mingw32/lib. I was able to solve the problem by linking it to the /mingw32/lib folder:
ln -s /usr/lib/libdl.a /mingw32/lib

OpenKinect: Compile custom code on MAC

Can someone please tell me how to compile custom kinect code on MAC.
I have downloaded and built the OpenKinect as instructed by the guide(and yes glview works fine)
I am following this: http://openkinect.org/wiki/C%2B%2B_GL_Example
But I am not able to produce any output file.
g++ -g -Wall `pkg-config --cflags libfreenect` -lopengl32 -lglut32 `pkg-config --libs libfreenect` -lGL -lGLU -lglut -c main.cpp
Package libfreenect was not found in the pkg-config search path.
Perhaps you should add the directory containing `libfreenect.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libfreenect' found
Package libfreenect was not found in the pkg-config search path.
Perhaps you should add the directory containing `libfreenect.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libfreenect' found
In file included from main.cpp:27:
/usr/local/include/libfreenect.hpp:29:25: error: libfreenect.h: No such file or directory
In file included from main.cpp:27:
/usr/local/include/libfreenect.hpp:46: error: expected `)' before ‘*’ token