[R-pkg-devel] Reproducing CRAN checks

[Dirk Eddelbuettel]

On 4 September 2025 at 21:30, Pepijn de Vries wrote:
| when not found. 3) "Could not find the required static library BLOSC"
| Here Prof. Ripley implies that blosc is not static on Linux. I don't think this is
| the case. So I'm not sure how to proceed with this.

What is your system / your reference?  "Here" on Ubuntu libblosc* is set up
like thousands of other libraries: the shared library in the run-time
package, the static library in the -dev package.

Your build picks up the shared library as we'd expect:

$ ldd /usr/local/lib/R/site-library/blosc/libs/blosc.so | grep blosc
        libblosc.so.1 => /lib/x86_64-linux-gnu/libblosc.so.1 (0x00007f4b56501000)
$

To pick just one other package with compressors libraries:

$ ldd /usr/local/lib/R/site-library/zip/libs/zip.so | grep 'lib.*z'
        libzstd.so.1 => /lib/x86_64-linux-gnu/libzstd.so.1 (0x000078af0e90f000)
        liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x000078af0e8cf000)
        libbz2.so.1.0 => /lib/x86_64-linux-gnu/libbz2.so.1.0 (0x000078af0e8bb000)
        libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x000078af0e89d000)
$

Now, it has become a little 'fashionable' to ship libraries with their CRAN
package and embed them, but the default is still to rely on established
system libraries:

$ ldd /usr/local/lib/R/site-library/RPostgreSQL/libs/RPostgreSQL.so | grep libpq
        libpq.so.5 => /lib/x86_64-linux-gnu/libpq.so.5 (0x000071fe7fc53000)
$ ldd /usr/local/lib/R/site-library/RPostgres/libs/RPostgres.so | grep libpq
        libpq.so.5 => /lib/x86_64-linux-gnu/libpq.so.5 (0x000072e718fd6000)
$

Maybe Prof Ripley wanted you to play along the common theme of relying on an
external shared library?  For libblosc the default (as seen from `pkgconf`
aka `pkg-config`) appears to be standard linking just as we saw above:

$ pkgconf --libs blosc
-lblosc 
$ 

Hope this helps,  Dirk

-- 
dirk.eddelbuettel.com | @eddelbuettel | edd using debian.org