GNU Scientific Library undefined reference to xx issue - gsl

Question

I’m struggling with GSL, I’m on Ubuntu 14.04 and have just installed GSL.
I downloaded the latest GSL release, and ran ./configure in the extracted folder, then sudo make, and after that sudo make install.
Everything seems to have worked fine during the installation.
I’ve tried some basic examples from the documentation. The first example from this page works great.
But this example does not work. I get the following error:
simon#simon-bnt:~/Skrivbord/gsl-test$ gcc main.c -o main -lgsl -lgslcblas -lm
/tmp/cclZjB9J.o: I funktionen "main":
main.c:(.text+0xe): undefined reference to gsl_interp2d_bilinear
main.c:(.text+0x88): undefined reference to gsl_spline2d_alloc
main.c:(.text+0xbc): undefined reference to gsl_spline2d_set
main.c:(.text+0xde): undefined reference to gsl_spline2d_set
main.c:(.text+0x10e): undefined reference to gsl_spline2d_set
main.c:(.text+0x130): undefined reference to gsl_spline2d_set
main.c:(.text+0x156): undefined reference to gsl_spline2d_init
main.c:(.text+0x26b): undefined reference to gsl_spline2d_eval
main.c:(.text+0x308): undefined reference to gsl_spline2d_free
collect2: error: ld returned 1 exit status
So I googled for a while, found another way to reference the libraries needed:
simon#simon-bnt:~/Skrivbord/gsl-test$ gcc -o main main.c gsl-config --cflags --libs
simon#simon-bnt:~/Skrivbord/gsl-test$ ./main
./main: error while loading shared libraries: libgsl.so.19:
cannot open shared object file: No such file or directory`
But as you can see that did not work either.
I’d like to be able to compile the whole program into an executable file, so I’d rather link the libraries.
I’d be really happy for all the help I can get.

Answer 1

The gsl-config command prints arguments that are to be passed to the compiler and/or linker. For example, on my system:
$ gsl-config --cflags
-I/usr/include
$ gsl-config --libs
-L/usr/lib -lgsl -lgslcblas -lm
$
When you type:
gcc -o main main.c gsl-config --cflags --libs
you're not passing the output of gsl-config to gcc, you're passing the *string" gsl-config to gcc, and gcc doesn't know what to do with it.
I think the correct command line would be this, or something very similar to it:
gcc $(gsl-config --cflags) main.c -o main $(gsl-config --libs)
This assumes you're using some sh-derived shell that recognizes the $(...) syntax. If your interactive shell is csh or tcsh, you can use this:
gcc `gsl-config --cflags` main.c -o main `gsl-config --libs`
(You can use the backtick syntax with bash as well, but I find the $(...) syntax easier to use if it's available.)
(BTW, this didn't work for me, but it's likely I just haven't installed some required package.)

Answer 2

I suspect you have the libgsl* packages of the distribution shadowing your new installation. GSL version before 2.0 had no 2d-interpolation (IIRC) so it would explain how can compile (using your new headers) but not link.
Removing libgsl0-dev may be enough. You can then still run against Ubuntu packages depending on the run-time but allow you to build against your local gsl 2.0.
To prove that point, here is a copy&paste from a Docker session in a Debian testing container using the GSL 2.0 package. It then all works:
root#ab45b54cd90e:/tmp# gcc -o gsl_interp2d gsl_interp2d.c -lgsl -lgslcblas -lm
root#ab45b54cd90e:/tmp# ./gsl_interp2d | head
0.000000 0.000000 0.000000
0.000000 0.010101 0.010101
0.000000 0.020202 0.020202
0.000000 0.030303 0.030303
0.000000 0.040404 0.040404
0.000000 0.050505 0.050505
0.000000 0.060606 0.060606
0.000000 0.070707 0.070707
0.000000 0.080808 0.080808
0.000000 0.090909 0.090909
root#ab45b54cd90e:/tmp#
I did
apt-get update
apt-get install libgsl-dev
apt-get install build-essential # for gcc and friends
to get what is needed beyond the basic Docker container.