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.
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 trying to build heimdal package for msys2. To my dismay, during linking of the first constituent library, roken, dlls fail to be built, and that causes sort of a chain reaction further on.
The only message i get is:
libtool: undefined symbols not allowed in x86_64-pc-msys shared ... only static will be built
however, there is no information provided on what symbols are undefined. How can i find that out?
If i turn on output of commands wuth make V=1 i get libtool command that links from a large numbert of .lo files. If i try to run gcc over them (copying command from there), it does not recognize them as anything.
I am trying to follow instructions as outlined in msys2 package build script for heimdal.
On Windows building a shared library while allowing undefined symbols is not allowed.
Try to build with the -Wl,-no-undefined linker flag, for example by adding LDFLAGS="-Wl,-no-undefined" to the ./configure command.
If that didn't work try this after ./configure and before make:
sed -i.bak -e "s/\(allow_undefined=\)yes/\1no/" libtool
If you already had a failed build earlier you should also clean up any .la files like this before running make again:
rm $(find -name '*.la')
I am trying to link a locally installed shared library (./vendor/lib/libfoo.so) with my binary, ./bar. Unfortunately, none of my attempts generates a link with an absolute path to libfoo.so. As a consequence I need to use
LD_LIBRARY_PATH=vendor/lib ./bar
to run it, which I want to avoid. ldd bar shows me this:
linux-vdso.so.1 => (0x00007ffed5fd8000)
libbar.so.2 => not found
libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007fb9ea787000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fb9ea47d000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fb9ea267000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fb9e9e9d000)
/lib64/ld-linux-x86-64.so.2 (0x000055f326761000)
A word about libbar.so.2: the file exists (in vendor/lib) alongside libbar.so. Both are actually symlinks to libhts.so.1.6. That file also exists, and is the actual shared library.
Here’s the different ways I’ve tried:
FULL_PATH="$(pwd -P)/vendor/lib"
g++ -o bar bar.o -Lvendor/lib -lfoo # 1
g++ -o bar bar.o -L$FULL_PATH -lfoo # 2
g++ -o bar bar.o $FULL_PATH/libfoo.so # 3
g++ -o bar bar.o $FULL_PATH/libfoo.so.1.6 # 4
All of these variants produce identical ldd output, even the last line (does ld insist on using the highest version of a library?).
The only way I’ve found to make this work is to use
LD_RUN_PATH=$FULL_PATH g++ -o bar bar.o -Lvendor/lib -lfoo
(I can’t use -rpath because my version of g++ doesn’t understand this argument, and I’m using g++ instead of ld to get the libstdc++ dependencies right — I could use -Wl,-rpath of course.)
But I can’t help but feel that there should be a way of making this work without the use of environment variables/-rpath. I’ve found an answer specifically referencing symlinks to libraries but unfortunately it doesn’t help me (see attempt 4 above).
This is on Ubuntu 16.04, g++ 5.4.0, GNU ld 2.26.1, in case it matters.
It sounds likely that you didn't update the ldconfig cache after installing
your shared library in the non-standard location /what/ever/vendor/lib:-
sudo ldconfig /what/ever/vendor/lib
Until you do that the runtime linker will be unaware that libfoo.so is
in /what/ever/vendor/lib, even if it is, unless you prompt it at runtime through
the LD_LIBRARY_PATH environment variable.
Incidentally, it isn't a shortcoming of your version of g++ that it
doesn't recognize -rpath. This has only ever been a linker (ld) option,
never a GCC frontend option. So -Wl,-rpath=/what/ever/vendor/lib is the
conventional way of tacking the non-standard runtime library path to your
program so as to avoid relying on either the ldconfig cache or LD_LIBRARY_PATH
For out-of-the ordinary linkages it may be considered better to use -rpath
rather than extend the ldconfig cache, which has less discriminate effects.
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
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