Program is part of the Xenomai test suite, cross-compiled from Linux PC into Linux+Xenomai ARM toolchain.
# echo $LD_LIBRARY_PATH
/lib
# ls /lib
ld-2.3.3.so libdl-2.3.3.so libpthread-0.10.so
ld-linux.so.2 libdl.so.2 libpthread.so.0
libc-2.3.3.so libgcc_s.so libpthread_rt.so
libc.so.6 libgcc_s.so.1 libstdc++.so.6
libcrypt-2.3.3.so libm-2.3.3.so libstdc++.so.6.0.9
libcrypt.so.1 libm.so.6
# ./clocktest
./clocktest: error while loading shared libraries: libpthread_rt.so.1: cannot open shared object file: No such file or directory
Is the .1 at the end part of the filename? What does that mean anyway?
Your library is a dynamic library.
You need to tell the operating system where it can locate it at runtime.
To do so,
we will need to do those easy steps:
Find where the library is placed if you don't know it.
sudo find / -name the_name_of_the_file.so
Check for the existence of the dynamic library path environment variable(LD_LIBRARY_PATH)
echo $LD_LIBRARY_PATH
If there is nothing to be displayed, add a default path value (or not if you wish to)
LD_LIBRARY_PATH=/usr/local/lib
We add the desired path, export it and try the application.
Note that the path should be the directory where the path.so.something is. So if path.so.something is in /my_library/path.so.something, it should be:
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/my_library/
export LD_LIBRARY_PATH
./my_app
Reference to source
Here are a few solutions you can try:
ldconfig
As AbiusX pointed out: If you have just now installed the library, you may simply need to run ldconfig.
sudo ldconfig
ldconfig creates the necessary links and cache to the most recent
shared libraries found in the directories specified on the command
line, in the file /etc/ld.so.conf, and in the trusted directories
(/lib and /usr/lib).
Usually your package manager will take care of this when you install a new library, but not always, and it won't hurt to run ldconfig even if that is not your issue.
Dev package or wrong version
If that doesn't work, I would also check out Paul's suggestion and look for a "-dev" version of the library. Many libraries are split into dev and non-dev packages. You can use this command to look for it:
apt-cache search <libraryname>
This can also help if you simply have the wrong version of the library installed. Some libraries are published in different versions simultaneously, for example, Python.
Library location
If you are sure that the right package is installed, and ldconfig didn't find it, it may just be in a nonstandard directory. By default, ldconfig looks in /lib, /usr/lib, and directories listed in /etc/ld.so.conf and $LD_LIBRARY_PATH. If your library is somewhere else, you can either add the directory on its own line in /etc/ld.so.conf, append the library's path to $LD_LIBRARY_PATH, or move the library into /usr/lib. Then run ldconfig.
To find out where the library is, try this:
sudo find / -iname *libraryname*.so*
(Replace libraryname with the name of your library)
If you go the $LD_LIBRARY_PATH route, you'll want to put that into your ~/.bashrc file so it will run every time you log in:
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/path/to/library
Update
While what I write below is true as a general answer about shared libraries, I think the most frequent cause of these sorts of message is because you've installed a package, but not installed the -dev version of that package.
Well, it's not lying - there is no libpthread_rt.so.1 in that listing. You probably need to re-configure and re-build it so that it depends on the library you have, or install whatever provides libpthread_rt.so.1.
Generally, the numbers after the .so are version numbers, and you'll often find that they are symlinks to each other, so if you have version 1.1 of libfoo.so, you'll have a real file libfoo.so.1.0, and symlinks foo.so and foo.so.1 pointing to the libfoo.so.1.0. And if you install version 1.1 without removing the other one, you'll have a libfoo.so.1.1, and libfoo.so.1 and libfoo.so will now point to the new one, but any code that requires that exact version can use the libfoo.so.1.0 file. Code that just relies on the version 1 API, but doesn't care if it's 1.0 or 1.1 will specify libfoo.so.1. As orip pointed out in the comments, this is explained well at here.
In your case, you might get away with symlinking libpthread_rt.so.1 to libpthread_rt.so. No guarantees that it won't break your code and eat your TV dinners, though.
You need to ensure that you specify the library path during
linking when you compile your .c file:
gcc -I/usr/local/include xxx.c -o xxx -L/usr/local/lib -Wl,-R/usr/local/lib
The -Wl,-R part tells the resulting binary to also look for the library
in /usr/local/lib at runtime before trying to use the one in /usr/lib/.
Try adding LD_LIBRARY_PATH, which indicates search paths, to your ~/.bashrc file
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/path_to_your_library
It works!
The linux.org reference page explains the mechanics, but doesn't explain any of the motivation behind it :-(
For that, see Sun Linker and Libraries Guide
In addition, note that "external versioning" is largely obsolete on Linux, because symbol versioning (a GNU extension) allows you to have multiple incompatible versions of the same function to be present in a single library. This extension allowed glibc to have the same external version: libc.so.6 for the last 10 years.
cd /home/<user_name>/
sudo vi .bash_profile
add these lines at the end
LD_LIBRARY_PATH=/usr/local/lib:<any other paths you want>
export LD_LIBRARY_PATH
Another possible solution depending on your situation.
If you know that libpthread_rt.so.1 is the same as libpthread_rt.so then you can create a symlink by:
ln -s /lib/libpthread_rt.so /lib/libpthread_rt.so.1
Then ls -l /lib should now show the symlink and what it points to.
I had a similar error and it didn't fix with giving LD_LIBRARY_PATH in ~/.bashrc .
What solved my issue is by adding .conf file and loading it.
Go to terminal an be in su.
gedit /etc/ld.so.conf.d/myapp.conf
Add your library path in this file and save.(eg: /usr/local/lib).
You must run the following command to activate path:
ldconfig
Verify Your New Library Path:
ldconfig -v | less
If this shows your library files, then you are good to go.
running:
sudo ldconfig
was enough to fix my issue.
I had this error when running my application with Eclipse CDT on Linux x86.
To fix this:
In Eclipse:
Run as -> Run configurations -> Environment
Set the path
LD_LIBRARY_PATH=/my_lib_directory_path
Wanted to add, if your libraries are in a non standard path, run ldconfig followed by the path.
For instance I had to run:
sudo ldconfig /opt/intel/oneapi/mkl/2021.2.0/lib/intel64
to make R compile against Intel MKL
All I had to do was run:
sudo apt-get install libfontconfig1
I was in the folder located at /usr/lib/x86_64-linux-gnu and it worked perfectly.
Try to install lib32z1:
sudo apt-get install lib32z1
If you are running your application on Microsoft Windows, the path to dynamic libraries (.dll) need to be defined in the PATH environment variable.
If you are running your application on UNIX, the path to your dynamic libraries (.so) need to be defined in the LD_LIBRARY_PATH environment variable.
The error occurs as the system cannot refer to the library file mentioned. Take the following steps:
Running locate libpthread_rt.so.1 will list the path of all the files with that name. Let's suppose a path is /home/user/loc.
Copy the path and run cd home/USERNAME. Replace USERNAME with the name of the current active user with which you want to run the file.
Run vi .bash_profile and at the end of the LD_LIBRARY_PATH parameter, just before ., add the line /lib://home/usr/loc:.. Save the file.
Close terminal and restart the application. It should run.
I got this error and I think its the same reason of yours
error while loading shared libraries: libnw.so: cannot open shared
object file: No such file or directory
Try this. Fix permissions on files:
cd /opt/Popcorn (or wherever it is)
chmod -R 555 * (755 if not ok)
I use Ubuntu 18.04
Installing the corresponding -dev package worked for me,
sudo apt install libgconf2-dev
Before installing the above package, I was getting the below error:
turtl: error while loading shared libraries: libgconf-2.so.4: cannot open shared object file: No such file or directory
I got this error and I think its the same reason of yours
error while loading shared libraries: libnw.so: cannot open shared object
file: No such file or directory
Try this. Fix permissions on files:
sudo su
cd /opt/Popcorn (or wherever it is)
chmod -R 555 * (755 if not ok)
chown -R root:root *
A similar problem can be found here.
I've tried the mentioned solution and it actually works.
The solutions in the previous questions may work. But the following is an easy way to fix it.
It works by reinstalling the package libwbclient
in fedora:
dnf reinstall libwbclient
You can read about libraries here:
https://domiyanyue.medium.com/c-development-tutorial-4-static-and-dynamic-libraries-7b537656163e
There is a laptop on which I have no root privilege.
onto the machine I have a library installed using configure --prefix=$HOME/.usr .
after that, I got these files in ~/.usr/lib :
libXX.so.16.0.0
libXX.so.16
libXX.so
libXX.la
libXX.a
when I compile a program that invokes one of function provided by the library with this command :
gcc XXX.c -o xxx.out -L$HOME/.usr/lib -lXX
xxx.out was generated without warning, but when I run it error like this was thrown:
./xxx.out: error while loading shared libraries: libXX.so.16: cannot open shared object file: No such file or directory , though libXX.so.16 resides there.
my clue-less assumption is that ~/.usr/lib wasn't searched when xxx.out is invoked.
but what can I do to specify path of .so , in order that xxx.out can look there for .so file?
An addition is when I feed -static to gcc, another error happens like this:
undefined reference to `function_proviced_by_the_very_librar'
It seems .so does not matter even though -L and -l are given to gcc.
what should I do to build a usable exe with that library?
For other people who has the same question as I did
I found a useful article at tldp about this.
It introduces static/shared/dynamic loaded library, as well as some example code to use them.
There are two ways to achieve that:
Use -rpath linker option:
gcc XXX.c -o xxx.out -L$HOME/.usr/lib -lXX -Wl,-rpath=/home/user/.usr/lib
Use LD_LIBRARY_PATH environment variable - put this line in your ~/.bashrc file:
export LD_LIBRARY_PATH=/home/user/.usr/lib
This will work even for a pre-generated binaries, so you can for example download some packages from the debian.org, unpack the binaries and shared libraries into your home directory, and launch them without recompiling.
For a quick test, you can also do (in bash at least):
LD_LIBRARY_PATH=/home/user/.usr/lib ./xxx.out
which has the advantage of not changing your library path for everything else.
Should it be LIBRARY_PATH instead of LD_LIBRARY_PATH.
gcc checks for LIBRARY_PATH which can be seen with -v option
I'm have built and installed Cyassl-2.4.2 on my unix machine to use with a project of mine; however, when I try to compile my c project, the compiler cannot find the libcyassl.a file. I have searched many times in the Cyassl.2.4.2 folder and am unable to find the file myself. Where is this file locate? Have I missed a step in bulding/installing Cyassl.2.4.2? Thanks!
I had successfully built and installed CyaSSL 2.4.2 here and this is what I got:
~/cyassl$ find . -iname "*.a"
./src/.libs/libcyassl.a
~/cyassl$ ls /usr/local/lib/
libcyassl.a libcyassl.la libcyassl.so libcyassl.so.3 libcyassl.so.3.0.3
The building process used was:
./autogen.sh
./configure
make
sudo make install
The installation prints out:
Libraries have been installed in:
/usr/local/lib
If you ever happen to want to link against installed libraries
in a given directory, LIBDIR, you must either use libtool, and
specify the full pathname of the library, or use the -LLIBDIR'
flag during linking and do at least one of the following:
- add LIBDIR to theLD_LIBRARY_PATH' environment variable
during execution
- add LIBDIR to the LD_RUN_PATH' environment variable
during linking
- use the-Wl,-rpath -Wl,LIBDIR' linker flag
- have your system administrator add LIBDIR to `/etc/ld.so.conf'
See any operating system documentation about shared libraries for
more information, such as the ld(1) and ld.so(8) manual pages.
I am trying to compile one of the projects found here
USB-I2C/SPI/GPIO Interface Adapter.
I downloaded the i2c_bridge-0.0.1-rc2.tgz package. I installed libusb and that seemed to go well with no issues. I go into the i2c_bridge-0.0.1-rc2/ directory and make. That compiles. I move into the i2c_bridge-0.0.1-rc2/i2c folder and make. It compiles and gives me ./i2c. However, when I run it, it says error while loading shared libraries: libi2cbrdg.so: cannot open shared object file: No such file or directory
The makefile in i2c_bridge-0.0.1-rc2/i2c has the library directory as ../. The libi2cbrdg.so is in this directory (i2c_bridge-0.0.1-rc2). I also copied the file to /usr/local/lib. An ls of the i2c_bridge-0.0.1-rc2/ directory is
i2c i2cbrdg.d i2cbrdg.o libi2cbrdg.a Makefile tests
i2cbrdg.c i2cbrdg.h INSTALL libi2cbrdg.so README u2c4all.sh
(That i2c is a directory)
If I sudo ./i2c, it still gives me the problem.
I had to take away the -Werror and -noWdecrepated (spelling?) options in all the makefiles to get them to compile, but that shouldn't affect this should it?
What else is necessary for it to find the .so file? If anyone can help me find out what is wrong I would be very grateful. If more information is needed I can post it.
You have to distinguish between finding so's at compile-time and at run-time. The -L flag you give at compile-time has nothing to do with localizing the library at run-time. This is rather done via a number of variables and some paths embedded in the library.
The best hot-fix for this problem is often setting LD_LIBRARY_PATH to the directory with the .so file, e.g.:
$ LD_LIBRARY_PATH=.. ./i2c
For a long-term solution, you need to either have a close look at the whole LD system with rpath and runpath, or use libtool (which solves these issues for your portably).
Copying a file to /usr/local/lib is often insufficient because ld caches the available libraries, so you need to re-run ldconfig (as root) after you copied a library to /usr/local/lib.
If you are building the code from source that needs the the library, you can put the path that the library is in in the environment variable LD_RUN_PATH before building, and the linker will save that path into the binary, so that it will automatically be looked for in the right place at runtime.
Linux specific: Alternately, put the library in /lib, /usr/lib, or some other path referenced in your /etc/ld.so.conf or its imported config fragments, and then all you need to do is run /sbin/ldconfig to refresh ld.so (the dynamic linker)'s cache of libraries.
This works for my issue,hope will help anyone.
gcc test.c -Wl,-rpath /usr/local/lib -lfcgi -o test.fcg
And -Wl,-rpath option is the key trick.
I need to build two 3rd party shared libraries, so their .so files will be reused by other projects. However, after build one of these libraries contains hardcoded path to another. This path is invalid on other machines and causes linker warnings. How can I prevent the full path from being embedded in the resulting .so files?
Details:
First library source: ~/dev/A
Second library source: ~/dev/B
Both of them have configure script to generate make files. Library B depends on A. So, first I build A:
$ ~/dev/A/configure --prefix=~/dev/A-install
$ make && make install
Then I build B:
$ ~/dev/B/configure --prefix=~/dev/B-install --with-A=~/dev/A-install
$ make && make install
Then I want to upload the contents of ~/dev/A-install and ~/dev/B-install to our file server, so other teams and build machines can use the binaries. But they get linker warnings when they try to use B:
/usr/bin/ld: warning: libA.so.2, needed by /.../deps/B/lib/libB.so, not found (try using -rpath or -rpath-link)
When I run ldd libB.so it gives:
...
libA.so.2 => /home/alex/dev/A-install/lib/libA.so.2
Obviously this path exists only on my machine and cannot be found on other machines.
How can I remove full hardcoded path from libB.so?
Thanks.
You have to use --prefix value that will be valid in the runtime environment for both packages!
Than you override prefix or DESTDIR (prefix replaces the prefix, DESTDIR is prepended to it, but works more reliably) on the make command-line when installing. Like:
~/dev/A$ ./configure
~/dev/A$ make
~/dev/A$ make install prefix=~/dev/A-install
~/dev/B$ ./configure --with-A=~/dev/A-install
~/dev/B$ make
~/dev/B$ make install prefix=~/dev/B-install
or (which is preferred and is how all package-building tools use it):
~/dev/A$ ./configure
~/dev/A$ make
~/dev/A$ make install DESTDIR=~/dev/A-install
~/dev/B$ ./configure --with-A=~/dev/A-install/usr/local
~/dev/B$ make
~/dev/B$ make install prefix=~/dev/B-install
because this way you are installing to ~/dev/A-install/$prefix, so with default prefix ~/dev/A-install/usr/local. The advantage of this later option is, that if you redefine some specific installation paths without refering to prefix (say --sysconfdir=/etc), DESTDIR will still get prepended to it, while it won't be affected by prefix.
-Wl,-rpath,~/deps/A/lib:~/deps/B/lib:~/dev/MyApp/bin
This linker option is responsible for saving the path inside the library. You need somehow to remove this.
See with ./configure --help if there's some option that could influence this. Another option is to edit manually the makefile and remove this option.
== edit2 ==
One more thing
-L~/deps/A/lib -L~/deps/B/lib ~/deps/A/lib/libA.so ~/deps/B/lib/libB.so
If libA.so and libB.so don't have SONAME, linking them like "~/deps/A/lib/libA.so" will also cause saving the path. Soname is set using -Wl,-soname,<soname> linker option when building shared library.
If soname is set in the shared library, linking it using "~/deps/A/lib/libA.so" form is ok.
Like Jan mentioned in the comments, the better way is using "-Llibrary/path -llibrary_name" without rpath.
-L~/deps/A/lib -L~/deps/B/lib -lA -lB
When I run ldd libB.so it gives:
libA.so.2 => /home/alex/dev/A-install/lib/libA.so.2
The low-level solution to this problem is to use the option "-soname=libA.so" when you link the libA.so library. By having SONAME defined for a shared object, the linker will not embed absolute paths when linking against that shared object.
The OP is using "configure", so this isn't an easy solution to implement unless he is willing to go into the bowels of the Makefile generated by the configure script.
Shared libraries and executables have a list of directories to look for shared libraries, in addition to the list in the operating system's configuration. RPATH is used to add shared library search paths, used at runtime.
If you want a relative path to be used in RPATH, there is a special syntax that most Linux/UNIX (but not AIX) systems support - $ORIGIN or ${ORIGIN}.
$ORIGIN will expand at runtime to the directory where the binary resides - either the library or executable.
So if you put executable binaries in prefix/bin/ and shared libraries in prefix/lib/ you can add an entry to RPATH like ${ORIGIN}/../lib and this will expand at runtime to prefix/bin/../lib/
It's often a little trick to get the syntax correct in a Makefile, because you have to escape the $ in ORIGIN so it will not be expanded. It's typical to do this in a Makefile:
g++ -Wl,-rpath=\$${ORIGIN}/../lib
Both Make and the shell will want to look in your environment for a variable called ORIGIN - so it needs to be double-escaped.
I just got caught out thinking I had the same problem.
None of the above answers helped me.
Whenever I tried
ldd libB.so
I would get in the output:
libA.so.1 => /home/me/localpath/lib/libA.so.1.0
and so I thought I had a hardcoded path. Turns out that I had forgotten I had LD_LIBRARY_PATH set for local testing. Clearing LD_LIBRARY_PATH meant that ldd found the correct installed library in /usr/lib/
Perhaps using the -rpath and -soname options to ld could help (assuming a binutils or binutils.gold package for ld on a recent Linux system)?