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compilationlinkerdynamic-library

Using dynamic library

When I would like to compile a program which uses a dynamic library, do I have to install (i.e. copy to a specific place, say, /usr/share/lib) this library? Or is it ok, if I put this library to any place somewhere and later during linking I point the linker to it, e.g. '-L ./thelibfolder'?

Solution

  • do I have to install (i.e. copy to a specific place, say, /usr/share/lib) this library?

    No.

    For a UNIX shared library, you need to arrange for two things:

    • You have to make the library known to the static linker, while linking main executable. Usually this is achieved by adding -L/path/to/directory -lfoo link flags to the link line.
    • You have to make runtime loader search /path/to/directory as well. This is system-specific. On many systems, setting LD_LIBRARY_PATH environment variable achieves the desired result, though this is usually not the preferred method. Another method is to encode this path into the application itself, e.g. on Linux one would add -Wl,-rpath=/path/to/directory to the application link line.