What is LD_LIBRARY_PATH and how to use it?

java c++ environment-variables jacob
karla picture karla · Aug 22, 2011 · Viewed 118k times · Source

I take part in developing a Java project, which uses some C++ components, thus I need Jacob.dll. (on Windows 7)

I keep getting java.lang.UnsatisfiedLinkError: no JacobDB in java.library.path no matter where I put Jacob.dll....

I looked for possible decisions and the one that I haven't tried so far is setting the LD_LIBRARY_PATH variable, pointing at the .dll file.

I have little experience and I'm not familiar with what should be the meaning and usage of that variable - can you help me?

Answer

Alok Save picture Alok Save · Aug 22, 2011

LD_LIBRARY_PATH is the predefined environmental variable in Linux/Unix which sets the path which the linker should look in to while linking dynamic libraries/shared libraries.

LD_LIBRARY_PATH contains a colon separated list of paths and the linker gives priority to these paths over the standard library paths /lib and /usr/lib. The standard paths will still be searched, but only after the list of paths in LD_LIBRARY_PATH has been exhausted.

The best way to use LD_LIBRARY_PATH is to set it on the command line or script immediately before executing the program. This way the new LD_LIBRARY_PATH isolated from the rest of your system.

Example Usage: 

$ export LD_LIBRARY_PATH="/list/of/library/paths:/another/path"
$ ./program

Since you talk about .dll you are on a windows system and a .dll must be placed at a path which the linker searches at link time, in windows this path is set by the environmental variable PATH, So add that .dll to PATH and it should work fine.

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