[petrasovaa]

I had trouble configuring GRASS with cmake and this PR is what my AI suggested. It solved the problem for me.

AI summary

When both lapacke.pc and openblas.pc are present, _search_lapacke_pkgs overwrites LAPACKE_PKGCONFIG on every iteration, so openblas (last in the list) always wins. On Debian/Ubuntu the openblas-pthread variant doesn't ship LAPACKE symbols, so the LAPACKE_dgesv check links only libopenblas.so and fails:

Could NOT find LAPACKE (missing: HAVE_LAPACKE_DGESV) (found version "0.3.26")

Add break() so the first match wins, matching the documented "lapacke and openblas... in that order" priority.

[echoix]

Makes sense with the intention written out in the header of the file

[nilason]

Sorry for late reaction, been travelling. Make sense, thanks!

[tmszi]

With your changes, I get compilation error message under Gentoo GNU/Linux (with enabled lapack USE flag)

-- Found CBLAS: TRUE (found version "0.3.32")
-- Looking for LAPACKE_dgesv
-- Looking for LAPACKE_dgesv - not found
CMake Error at /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:290 (message):
  Could NOT find LAPACKE (missing: HAVE_LAPACKE_DGESV) (found version
  "3.12.0")
Call Stack (most recent call first):
  /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:654 (_FPHSA_FAILURE_MESSAGE)
  cmake/find_scripts/FindLAPACKE.cmake:108 (find_package_handle_standard_args)
  cmake/modules/CheckDependentLibraries.cmake:224 (find_package)
  CMakeLists.txt:155 (include)

Successful compilation log without your changes:

-- Found CBLAS: TRUE (found version "0.3.32")
-- Looking for LAPACKE_dgesv
-- Looking for LAPACKE_dgesv - found
-- Found LAPACKE: TRUE (found version "0.3.32")
-- Found OpenMP_C: -fopenmp (found version "4.5")

[nilason]

With your changes, I get compilation error message under Gentoo GNU/Linux (with enabled lapack USE flag)

Do you have openblas installed?

[tmszi]

With your changes, I get compilation error message under Gentoo GNU/Linux (with enabled lapack USE flag)

Do you have openblas installed?

Yes I have.

tomas@gentoo-gnu-linux:~$ eix openblas
[I] sci-libs/openblas
     Available versions:  0.3.30-r5^td 0.3.31^td 0.3.32^td ~0.3.33^td {cpudetection eselect-ldso index64 openmp pthread relapack test}
     Installed versions:  0.3.32^td(01:21:49 PM 05/22/2026)(openmp -cpudetection -index64 -pthread -relapack -test)
     Homepage:            https://github.com/OpenMathLib/OpenBLAS
     Description:         Optimized BLAS library based on GotoBLAS2

[nilason]

With your changes, I get compilation error message under Gentoo GNU/Linux (with enabled lapack USE flag)

Do you have openblas installed?

Yes I have.

That explains why it used to work, because it ended up using openblas, even though the lapacke package was found (but obviously didn't have LAPACKE_dgesv). Each package found must also be checked, as soon as I find the time I'll make a PR for this. The FindCBLAS, has the same issues. Meanwhile, you should be able to set it manually with -D LAPACKE_PKGCONFIG=openblas.