How To Set DT_RUNPATH or How To Augment dlopen() Search Path, At Link-time?

Posted on 2004-08-29
Last Modified: 2008-01-09
I'm linking an executable, on Linux (SuSE version 9.1, kernel version 2.6.6, ld version, gcc version 3.2.3 (old)), and I want to augment the shared library path used by dlopen().  In the manpage on that system, it says that, in addition to all the standard places to look, dlopen() will use DT_RUNPATH or fall back on DT_RPATH.

During the link (I use gcc as a front-end to ld), I specify '-Wl,-rpath,LOCATION' (equivalent to calling ld w/ '-rpath LOCATION'), among other options, yet dlopen() fails to find the library in LOCATION.  On an older system (SuSE version 9.0, kernel version 2.4.21, ld version, gcc version 3.2.3 (same)), dlopen() succeeds.  On either system, if I put LOCATION in LD_LIBRARY_PATH, dlopen() succeeds, yet that's an unreasonable requirement for this application.

I'm aware of the tool chrpath (, but I want to know if there's a more straight-forward way to set DT_RUNPATH.  Such as via the command-line for ld.

BTW, isn't it a bit strange that someone had to write a dedicated tool for doing that?  Is it really true that binutils contains nothing for dumping or modifying DT_RPATH or DT_RUNPATH (or similar labels)?
Question by:videocoder
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
LVL 38

Expert Comment

ID: 11928748
In command line:

for sh/ksh/bash
you do:


or simply use LD_LIBRARY_PATH

For csh/tcsh
setenv LD_LIBRARY_PATH           $LD_LIBRARY_PATH:/path-to-lib

you can you them in your .profile (sh/ksh/bash) or .cshrc file (csh/tcsh)

Author Comment

ID: 11928841
Huh?  Are you sure about that?

DT_RUNPATH is not documented as an environment variable related to ld, in it the ld manpage.  Furthermore, this seems to make no difference in the behavior I'm seeing, and running 'strings' on my program shows that the path I put in the DT_RUNPATH environment variable didn't even make it into the executable.

Finally, as I think the subject and question clearly state, I am looking for an ALTERNATIVE to using LD_LIBRARY_PATH (which must be specified at runtime, rather than link-time).

I appreciate your attempt to help, but it seems like you didn't try to read or understand the question very thoroughly.
LVL 38

Expert Comment

ID: 11928994
I have never used "DT_RUNPATH", I thought you want to define such a var for your app,
a lot of app defined their only ENV vars. I have use something like LD_RUN_PATH.
The Orion Papers

Are you interested in becoming an AWS Certified Solutions Architect?

Discover a new interactive way of training for the exam.


Author Comment

ID: 11929056
Sorry, I assumed people wouldn't try to answer the question without actually knowing about DT_RPATH and DT_RUNPATH.  They're described in the dlopen() manpage as 'tags' in an ELF file.

I don't know much about ELF files, and I don't know what a 'tag' is, but I assume it's different from a 'section' or a 'symbol'.

Accepted Solution

mtmike earned 500 total points
ID: 11932758
DT_RPATH and DT_RUNPATH are entries in the dynamic table. You can dump the dynamic table using "objdump -p /path/to/binary".

The manual page of dlopen() seems to suggest that RUNPATH is searched, but this is not the case. See

Using '-Wl,-rpath,LOCATION' should set RPATH and not RUNPATH. If the SUSE 9.1 linker does set RUNPATH, try passing '-Wl,-disable-new-dtags' to gcc.

Author Comment

ID: 11939009
BTW, for the sake of anyone else reading this solution, I just wanted to note that '-rpath' appears to set both DT_RPATH and DT_RUNPATH (on the SuSE 9.1, kernel 2.6 system in question).

Featured Post

Free Tool: ZipGrep

ZipGrep is a utility that can list and search zip (.war, .ear, .jar, etc) archives for text patterns, without the need to extract the archive's contents.

One of a set of tools we're offering as a way to say thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Have you ever been frustrated by having to click seven times in order to retrieve a small bit of information from the web, always the same seven clicks, scrolling down and down until you reach your target? When you know the benefits of the command l…
The purpose of this article is to fix the unknown display problem in Linux Mint operating system. After installing the OS if you see Display monitor is not recognized then we can install "MESA" utilities to fix this problem or we can install additio…
There are cases when e.g. an IT administrator wants to have full access and view into selected mailboxes on Exchange server, directly from his own email account in Outlook or Outlook Web Access. This proves useful when for example administrator want…
In this brief tutorial Pawel from AdRem Software explains how you can quickly find out which services are running on your network, or what are the IP addresses of servers responsible for each service. Software used is freeware NetCrunch Tools (https…

695 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question