If the port installs one or more shared libraries, define a USE_LDCONFIG make variable, which will instruct a bsd.port.mk to run ${LDCONFIG} -m on the directory where the new library is installed (usually PREFIX/lib) during post-install target to register it into the shared library cache. This variable, when defined, will also facilitate addition of an appropriate @exec /sbin/ldconfig -m and @unexec /sbin/ldconfig -R pair into pkg-plist, so that a user who installed the package can start using the shared library immediately and de-installation will not cause the system to still believe the library is there.

USE_LDCONFIG=	yes

The default directory can be overridden by setting USE_LDCONFIG to a list of directories into which shared libraries are to be installed. For example, if the port installs shared libraries into PREFIX/lib/foo and PREFIX/lib/bar use this in Makefile:

USE_LDCONFIG=	${PREFIX}/lib/foo ${PREFIX}/lib/bar

Please double-check, often this is not necessary at all or can be avoided through -rpath or setting LD_RUN_PATH during linking (see lang/mosml for an example), or through a shell-wrapper which sets LD_LIBRARY_PATH before invoking the binary, like www/seamonkey does.

When installing 32-bit libraries on 64-bit system, use USE_LDCONFIG32 instead.

If the software uses autotools, and specifically libtool, add USES=libtool.

When the major library version number increments in the update to the new port version, all other ports that link to the affected library must have their PORTREVISION incremented, to force recompilation with the new library version.