linker not finding shared lapack and blas, but I am pointing right to it

Question

I am trying to build a .so that dynamically links against lapack and blas at runtime. When building, the linker complains that it cannot find lapack and blas, but I am pointing right to them (I think). What else might I be missing?

I am on a Rocky 9 Linux system (pretty fresh install). Among other things, I have done yum install gcc-gfortran lapack-3.9.0-8.el9.x86_64 compat-libgfortran-48-4.8.5-36.5.el9.x86_64 openblas-serial lapack scalapack-common and also yum groupinstall "Development tools". Some of these were done to (successfully) get old binaries working again, but I include them in case they might be interfering now. With yum list, I don't see anything else promising to install.

In /usr/lib64/ I see (among other things):

lrwxrwxrwx.  1 root root       18 May 25  2022 liblapack.so.3.9 -> liblapack.so.3.9.0*
lrwxrwxrwx.  1 root root       19 May 25  2022 liblapacke.so.3.9 -> liblapacke.so.3.9.0*
lrwxrwxrwx.  1 root root       19 May 25  2022 liblapacke.so.3 -> liblapacke.so.3.9.0*
-rwxr-xr-x.  1 root root  7496688 May 25  2022 liblapack.so.3.9.0*
-rwxr-xr-x.  1 root root  2908088 May 25  2022 liblapacke.so.3.9.0*
lrwxrwxrwx.  1 root root       18 Jan 18 16:18 liblapack.so.3 -> liblapack.so.3.9.0*
lrwxrwxrwx.  1 root root       22 May 16  2022 libopenblas.so.0 -> libopenblas-r0.3.15.so*
lrwxrwxrwx.  1 root root       23 May 16  2022 libopenblaso.so.0 -> libopenblaso-r0.3.15.so*
-rwxr-xr-x.  1 root root 38111888 May 16  2022 libopenblas-r0.3.15.so*
-rwxr-xr-x.  1 root root 39653512 May 16  2022 libopenblaso-r0.3.15.so*
lrwxrwxrwx.  1 root root       17 May 25  2022 libcblas.so.3.9 -> libcblas.so.3.9.0*
lrwxrwxrwx.  1 root root       16 May 25  2022 libblas.so.3.9 -> libblas.so.3.9.0*
-rwxr-xr-x.  1 root root   119640 May 25  2022 libcblas.so.3.9.0*
-rwxr-xr-x.  1 root root   583120 May 25  2022 libblas.so.3.9.0*
lrwxrwxrwx.  1 root root       19 Jun  2  2022 libflexiblas.so.3 -> libflexiblas.so.3.0*
lrwxrwxrwx.  1 root root       24 Jun  2  2022 libflexiblas_mgmt.so.3 -> libflexiblas_mgmt.so.3.0*
lrwxrwxrwx.  1 root root       23 Jun  2  2022 libflexiblas_api.so.3 -> libflexiblas_api.so.3.0*
-rwxr-xr-x.  1 root root  3870704 Jun  2  2022 libflexiblas.so.3.0*
-rwxr-xr-x.  1 root root    53256 Jun  2  2022 libflexiblas_mgmt.so.3.0*
-rwxr-xr-x.  1 root root    15912 Jun  2  2022 libflexiblas_api.so.3.0*
lrwxrwxrwx.  1 root root       17 Jan 18 16:18 libcblas.so.3 -> libcblas.so.3.9.0*
lrwxrwxrwx.  1 root root       16 Jan 18 16:18 libblas.so.3 -> libblas.so.3.9.0*

In addition, whereis liblapack.so and whereis libblas.so both come up empty-handed.

Following what I see here, I have done:

gcc -Wall -fPIC -O -g -fopenmp mylib.c -c -o mylib.pic.o
gcc -shared -fopenmp mylib.pic.o -L/usr/lib64 -lblas -llapack -lm -o mylib.so

but I get

/usr/bin/ld: cannot find -lblas
/usr/bin/ld: cannot find -llapack
collect2: error: ld returned 1 exit status

I know about this, but it seems wrong that I would have to get into system directories and manually make soft links in order to use standard infrastructure. There must be a "right" solution I am missing.

Thanks for any help.

Answer 1

I am pointing right to them (I think).

No, you are not. You need libblas.so, which is not the same as libblas.so.3.

The libblas.so is needed to link new binaries against libblas. The libblas.so.3 is needed to run already linked binaries.

Usually the .so libraries are installed as part of libblas-devel or a similar package.

Answer 2

Thanks to the answer from @EmployedRussian that pointed me in the right direction. For any other sophomore sys-admins stumbling on this, the rest of the story is that it seems that yum on Fedora systems is being overtaken by dnf. The instructions here are good (also for Rocky 9), and this searchable site is very useful for knowing what is available.

Long story short, this fixed my problem:

dnf --enablerepo=crb install blas-devel lapack-devel