How to specify (non-R) library path for dynamic library loading in R?

Question

I keep getting the following error when attempting to install readxl or haven in R (both dependencies of tidyverse) post-compilation, when the installer runs the loading test:

** testing if installed package can be loaded
Error in dyn.load(file, DLLpath = DLLpath, ...) :
  unable to load shared object '<my_lib_Path>/readxl/libs/readxl.so':
  <my_lib_path>/readxl/libs/readxl.so: undefined symbol: libiconv
Error loading failed

I have libiconv.so in a local lib path (not for R packages) that is included in LD_LIBRARY_PATH and I've verified in my R session that Sys.getenv("LD_LIBRARY_PATH") has that directory. Why can't R's dynamic library loader find this shared object? Is there a different R-specific environment variable I need to define to have the dynamic library loader in R search my local lib path?

Please note that this is not an issue with an R library path, but instead for a non-R dependency that an R package has. If I were compiling and linking C++ code, gcc would use ld, and hence LD_LIBRARY_PATH to track down dynamic dependencies. R doesn't appear to respect this rather common approach, and I can't seem to find any documentation on how to manage these more fine-grained dependency issues.

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Additional Details

!> sessionInfo()
 R version 3.3.3 (2017-03-06)
 Platform: x86_64-pc-linux-gnu (64-bit)
 Running under: CentOS Linux 7 (Core)

 locale:
  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
  [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
  [7] LC_PAPER=en_US.UTF-8       LC_NAME=C
  [9] LC_ADDRESS=C               LC_TELEPHONE=C
 [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

 attached base packages:
 [1] stats     graphics  grDevices utils     datasets  methods   base
 > 

I had previously compiled libiconv because it was a dependency for something else (don't recall what now - likely not an R package given current problems). I tried reinstalling it, but made no difference.

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Edit

I have also tried manually loading the library prior to installation:

> dyn.load(".local/lib/libiconv.so")
> is.loaded("libiconv")
[1] TRUE
> install.packages("tidyverse")

but it fails just as above.

Answer 1

Normally, the iconv method is picked up from glibc, which is linked to during build of the R packages in question. For whatever reason, however, iconv is getting resolved to libiconv in this case, but it is not linked by the R packages during build.

Original Workaround

One can make the linking to libiconv explicit by adding the following line to the haven/src/Makevars source file

PKG_LIBS=-liconv

which then let's you install from source R CMD INSTALL haven. However, editing packages feels hacky, plus this is something that will need to be done every upgrade, which sounds like a hassle.

Cleaner Workaround

Another option is to use withr::with_makevars, which allows one to temporarily control Makevars content. With this technique, one can install directly from the repo:

withr::with_makevars(c(PKG_LIBS="-liconv"), install.packages("haven"), assignment="+=")

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Credit: @knb suggested that I inspect the readxl.so with ldd and this turned out to be super useful because it showed that the shared object wasn't even trying to link to libiconv. Knowing that, I realized I could manually add the reference via the -liconv flag. Thanks @knb!

Additional Info

On the package side of things, relevant details about connecting libraries to R packages can be found in the guide for building libraries. On the system configuration side, the R-admin guide has some useful sections.

Answer 2

Are you running the code in RStudio Server? If so, the answer here may be useful.

I used to meet a similar error while loading dynamic library. The library was in a path contained in LD_LIBRARY_PATH. When I ran the code in R console, it could load the dynamic library correctly. But when I ran it in RStudio, the same error in your post raised.

The reason is that RStudio Server has its own library search path environment. You should specify the following configuration in /etc/rstudio/rserver.conf:

rsession-ld-library-path=/usr/lib64/:/usr/local/lib/:OTHER_PATH_OF_YOUR_LIB

Restart RStudio Server and the error should be fixed.