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
Related
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 $(pkg-config --cflags --libs openblas) -o foo
I am using cmake 3.10.2. I have both openmpi and mpich installed. However I need to load only mpich. So I found from the documentation the following
MPI_EXECUTABLE_SUFFIX
A suffix which is appended to all names that are being looked for.
For instance you may set this to .mpich or .openmpi to prefer the one
or the other on Debian and its derivatives.
My CMake file goes like this
set(MPI_EXECUTABLE_SUFFIX ".mpich")
FIND_PACKAGE(MPI REQUIRED)
INCLUDE_DIRECTORIES(${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
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.
In my makefile I have:
g++ -o Out Out.o -I Headers_Directory -L Libraries_Directory -lFile1 -lFile2
In my Libraries_Directory I have two files libFile1.a and libFile2.so
ld finds libFile1.a but cannot find libFile2.so. How that is possible and how can I resolve the issue?
I am compiling in Cygwin and using GNU gcc-g++ compiler.
A minimalist that regenerates the error:
Download the Linux Version of Gurobi here. Then, install the software using this instruction. You need to activate the software by obtaining a license from here. Free academic license for research purpose is available. Finally navigate to the following folder
installation_directory/gurobi701/linux64/examples/build
and issue the command make. You have to compile on Cygwin with GNU gcc-g++ compiler.
When I try to compile a simple c++ file using Magick++ and cygwin, I keep getting this result:
$ g++ -o imageTest imageTest.cpp `GraphicsMagick++-config --cppflags --cxxflags --ldflags --libs`
g++: unrecognized option `-no-undefined'
/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../../i686-pc-cygwin/bin/ld: cannot find -ldpstk
collect2: ld returned 1 exit status
I installed ImageMagick through the cygwin gui setup.
GraphicsMagick and ImageMagick are two different libraries. If you want to build your program using ImageMagick, as you state, it's just a matter of changing
GraphicsMagick++-config
into
Magick++-config
This should work. As for GraphicsMagick, it looks like the current -devel library in Cygwin is broken, as it requires a library (libdpstk) which is no longer available. (Have a look here if you are interested.)