A shared object is an indivisible unit that is generated from one or more relocatable objects. Shared objects can be bound with dynamic executables to form a runable process. As their name implies, shared objects can be shared by more than one application.
Simply put, A shared library/ Dynamic Library is a library that is loaded dynamically at runtime for each application that requires it. … They load only a single copy of the library file in memory when you run a program, so a lot of memory is saved when you start running multiple programs using that library.
There are four steps:
- Compile C++ library code to object file (using g++)
- Create shared library file (. SO) using gcc –shared.
- Compile the C++ code using the header library file using the shared library (using g++)
- Set LD_LIBRARY_PATH.
- Run the executable (using a. out)
- Step 1: Compile C code to object file.
According to the FHS, most libraries should be installed in /usr/lib, but libraries required for startup should be in /lib and libraries that are not part of the system should be in /usr/local/lib.
What is lib a file?
A LIB file contains a library of information used by a specific program. It may store a variety of information, which may include functions and constants referenced by a program or actual objects, such as text clippings, images, or other media. … Windows dynamic libraries typically have a . DLL file extension.
The shared objects are not included into the executable component but are tied to the execution. Dynamically loaded/unloaded and linked during execution (i.e. browser plug-in) using the dynamic linking loader system functions.
Shared libraries are the most common way to manage dependencies on Linux systems. These shared resources are loaded into memory before the application starts, and when several processes require the same library, it will be loaded only once on the system. This feature saves on memory usage by the application.
There are two workarounds.
- Just create a one line script in the same directory: ./my_program. and set Allow executing file as program in Nautilus. (Or add +x via chmod .)
- Open this directory in Terminal and run there. ( or drag and drop the file from Nautilus to Terminal)
Why is Ld_library_path bad?
LD_LIBRARY_PATH is an environment variable you set to give the run-time shared library loader (ld.so) an extra set of directories to look for when searching for shared libraries. … For security reasons, LD_LIBRARY_PATH is ignored at runtime for executables that have their setuid or setgid bit set.
If the program is already running, we can also get the list of loaded shared libraries by reading the file /proc/