Q: error while loading shared libraries
A: libyang is installed into the directory detected by CMake's GNUInstallDirs function. However, when it is connected with the installation prefix, the target directory is not necessary the path used by the system linker. Check the linker's paths in /etc/ld.so.conf.d/. If the path where libyang is installed is already present, just make ldconfig to rebuild its cache:
# ldconfig
If the path is not present, you can change the libyang installation prefix when running cmake, so the complete compilation and installation sequence is:
$ mkdir build; cd build $ cmake -DCMAKE_INSTALL_PREFIX:PATH=/usr .. $ make # make install
or add the libyang's location to the linker paths in /etc/ld.so.conf.d and then run ldconfig to rebuild the linker cache.
Q: yanglint(1) does not start, but prints the following error messages:
./yanglint libyang[0]: Invalid keyword "type" as a child to "annotation". (path: /) libyang[0]: Module "yang" parsing failed. Failed to create context.
A: To handle complex YANG extensions, libyang (and therefore yanglint(1)) needs plugins. By default, the plugins are installed into the system path (next to the libyang library into the separate libyang subdirectory). If libyang was not installed, yanglint cannot find these plugins and it fails. If you do not want to install libyang, it is possible to specify path to the plugins via environment variable. The plugins can be found in the libyang build directory in src/extensions/ subdirectory. So running yanglint(1) then can be made this way:
$ LIBYANG_EXTENSIONS_PLUGINS_DIR=`pwd`/src/extensions ./yanglint
The same issue occurs for user types and the solution is the same except they are built in src/user_types/ subdirectory and the path should be set with:
$ LIBYANG_USER_TYPES_PLUGINS_DIR=`pwd`/src/user_types
However, user types are not required for yanglint(1) to run properly.
Q: error (or similar) is printed:
Regular expression "<exp>" is not valid ("<exp>": support for \P, \p, and \X has not been compiled).
A: libyang uses PCRE library (not PCRE2) for regular expression parsing and evaluation. This error is printed because the locally installed PCRE library on your system is missing support for these regex atoms. It must be explicitly allowed by compiling PCRE with --enable-unicode-properties (more in its README).