runtime link path and g++

runtime link path and g++

[Wesley Smith]

Hi,
I'm trying to figure out how to manage shared library dependencies via
g++ on ubuntu 6.10.  I have a shared library I'm building that links
against some other shared libraries.  For reasons particular to my
project, I'm not putting the dependencies in /usr/lib but in a
completely different dir.  I can link against them just fine using -L,
but when I run ldd on the resulting lib, it can't find them.  Ideally,
I'd like to add the runtime link path aka LD_RUN_PATH "./" (i.e. path
of the lib itself).  How can I specify this path to g++?  I've seen -R
used in some places, but g++ doesn't understand it.

thanks,
wes

PS sorry for duplicate posting.  I had forgotten to change the subject line

Re: runtime link path and g++

[Eljay Love-Jensen]

Hi Wes,

> How can I specify this path to g++? I've seen -R used in some places, but g++
doesn't understand it.

This is a linker issue, not so much a GCC issue.  (Although it would be nice
for the GCC tool chain driver to be a little more rpath savvy across
platforms.)

Try -Wl,-rpath=/path/you/want or consider LD_LIBRARY_PATH=/path/you/want as
an environmental to your executable.

http://en.wikipedia.org/wiki/Rpath_(linking)

I'm not familiar with Ubuntu Linux, so it may do things slightly
differently.

For instance, I've heard that Ubuntu uses a different /bin/sh shell (dash
rather than bash), which results in x100 performance for their shell, and
lots of shell impedance mismatch from those who write bash-isms into what
probably should be /bin/sh clean.  The caveat is:  YMMV.

The rpath option has a few sharp edges.  When used with relative paths, it's
a security hole for the wily and devious.  If using absolute paths, it makes
the application much less mv-able.

The LD_LIBRARY_PATH option may necessitate having a user-convenience
launching script.  That allows your installer to construct the launching
script with all the right baked paths for LD_LIBRARY_PATH, or for the really
tricky, the launching script may figure out those setting dynamically from
how it was launched (using $0).

HTH,
--Eljay