Linux error while loading shared libraries: cannot open shared object file: No such file or directory

Question

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

Edit: OK I didn't notice the .1 at the end was part of the filename. What does that mean anyway?

Answer 1

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 http://www.linux.org/docs/ldp/howto/Program-Library-HOWTO/shared-libraries.html#AEN49

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.

Answer 2

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.

Answer 3

**

> **well this is very easy,,,just reformat the PC,,,reinstall the
> software and try again,**,,,

**