units installation error: Error in function udunits_init: Operating-system error. See "errno".

[wdkrnls]

I'm seeing a strange installation error on CentOS. It seems to compile just fine, but then fails at testing the install.

* installing *source* package ‘units’ ...
** package ‘units’ successfully unpacked and MD5 sums checked
configure: units: 0.6-2
checking whether the C++ compiler works... yes
checking for C++ compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C++ compiler... yes
checking whether /opt/rh/devtoolset-7/root/usr/bin/g++ accepts -g... yes
checking how to run the C++ preprocessor... /opt/rh/devtoolset-7/root/usr/bin/g++ -E
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking for stdbool.h that conforms to C99... no
checking for _Bool... no
checking for error_at_line... yes
checking for gcc... /opt/rh/devtoolset-7/root/usr/bin/gcc
checking whether we are using the GNU C compiler... yes
checking whether /opt/rh/devtoolset-7/root/usr/bin/gcc accepts -g... yes
checking for /opt/rh/devtoolset-7/root/usr/bin/gcc option to accept ISO C89... none needed
checking for XML_ParserCreate in -lexpat... yes
checking udunits2.h usability... yes
checking udunits2.h presence... yes
checking for udunits2.h... yes
checking for ut_read_xml in -ludunits2... yes
configure: creating ./config.status
config.status: creating src/Makevars
** libs
/opt/rh/devtoolset-7/root/usr/bin/g++ -I"/share/apps/R/R-3.5.1-openblas/lib64/R/include" -DNDEBUG -I/usr/include/udunits2 -I/usr/include/udunits2 -I/usr/local/include -I"/home/wdkrnls/R/lib/7/3.5/Rcpp/include" -I/usr/local/include   -fpic  -g -O2  -c RcppExports.cpp -o RcppExports.o
/opt/rh/devtoolset-7/root/usr/bin/gcc -I"/share/apps/R/R-3.5.1-openblas/lib64/R/include" -DNDEBUG -I/usr/include/udunits2 -I/usr/include/udunits2 -I/usr/local/include -I"/home/wdrknls/R/lib/7/3.5/Rcpp/include" -I/usr/local/include   -fpic  -I/share/apps/R/R-3.5.1-src/libs/include  -c io.c -o io.o
/opt/rh/devtoolset-7/root/usr/bin/g++ -I"/share/apps/R/R-3.5.1-openblas/lib64/R/include" -DNDEBUG -I/usr/include/udunits2 -I/usr/include/udunits2 -I/usr/local/include -I"/home/wdrknls/R/lib/7/3.5/Rcpp/include" -I/usr/local/include   -fpic  -g -O2  -c udunits.cpp -o udunits.o
/opt/rh/devtoolset-7/root/usr/bin/g++ -shared -L/share/apps/R/R-3.5.1-openblas/lib64/R/lib -L/share/apps/R/R-3.5.1-src/libs/lib -o units.so RcppExports.o io.o udunits.o -lexpat -lexpat -ludunits2 -L/share/apps/R/R-3.5.1-openblas/lib64/R/lib -lR
installing to /home/wdrknls/R/lib/7/3.5/units/libs
** R
** demo
** inst
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
** building package indices
** installing vignettes
** testing if installed package can be loaded
Error: package or namespace load failed for ‘units’:
 .onLoad failed in loadNamespace() for 'units', details:
  call: udunits_init(file.path(.get_ud_xml_dir(), "udunits2.xml"))
  error: Error in function udunits_init: Operating-system error.  See "errno".
Error: loading failed
Execution halted
ERROR: loading failed

[Enchufa2]

• How did you install udunits2? From EPEL or custom installation?
• How did you install units, using install.packages?
• What's the content of the environment variable UDUNITS2_XML_PATH?

[edzer]

Is it possible that you have multiple versions of udunits installed on you system, e.g. one manual and one packaged? (See r-spatial/sf#844)

[wdkrnls]

Enchufa2: It's possible that this environment variable was not defined, but I was trying to update with install.packages since I noticed this was failing when trying to update sf.

[Enchufa2]

You don't need to set that variable unless udunits2 is installed in a non-standard location.

[ladypolo19]

I'm sorry, I have the same problem and I don't know how to fix it