File: libtool.info,  Node: Finding the dlname,  Next: Dlopen issues,  Prev: Linking with dlopened modules,  Up: Dlopened modules

10.4 Finding the correct name to dlopen
=======================================

After a library has been linked with ‘-module’, it can be dlopened.
Unfortunately, because of the variation in library names, your package
needs to determine the correct file to dlopen.

   The most straightforward and flexible implementation is to determine
the name at runtime, by finding the installed ‘.la’ file, and searching
it for the following lines:

     # The name that we can dlopen.
     dlname='DLNAME'

   If DLNAME is empty, then the library cannot be dlopened.  Otherwise,
it gives the dlname of the library.  So, if the library was installed as
‘/usr/local/lib/libhello.la’, and the DLNAME was ‘libhello.so.3’, then
‘/usr/local/lib/libhello.so.3’ should be dlopened.

   If your program uses this approach, then it should search the
directories listed in the ‘LD_LIBRARY_PATH’(1) environment variable, as
well as the directory where libraries will eventually be installed.
Searching this variable (or equivalent) will guarantee that your program
can find its dlopened modules, even before installation, provided you
have linked them using libtool.

   ---------- Footnotes ----------

   (1) ‘LIBPATH’ on AIX, and ‘SHLIB_PATH’ on HP-UX.