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A shared library is a file containing object code that several a. out files may use simultaneously while executing. When a program is link edited with a shared library, the library code that defines the program’s external references is not copied into the program’s object file.
When the runtime linker creates the memory segments for a program, the dependencies tell what shared objects are needed to supply the program’s services. By repeatedly connecting referenced shared objects and their dependencies, the runtime linker generates a complete process image.
What is difference between static and shared library?
They are usually faster than the shared libraries because a set of commonly used object files is put into a single library executable file. One can build multiple executables without the need to recompile the file….Shared Libraries :
| properties | Static library | Shared library |
|---|---|---|
| Means | Performed by linkers | Performed by operating System |
How to get list of shared library dependencies?
To get a list of all shared library dependencies for a binary file, you can use the ldd utility. The output of ldd is in the form: This command shows all shared library dependencies for the ls command.
Dynamic or shared libraries can further be categorized into: Dynamically linked libraries – here a program is linked with the shared library and the kernel loads the library (in case it’s not in memory) upon execution. Dynamically loaded libraries – the program takes full control by calling functions with the library.
A program would typically use shared libraries rather than compiling and bundling all the required libraries into the program itself. It reduces program size and eases the development and distribution of the program. In Linux, shared libraries are normally stored in /lib* or /usr/lib*.
What are the two types of libraries in Linux?
Linux supports two classes of libraries, namely: Static libraries – are bound to a program statically at compile time. Dynamic or shared libraries – are loaded when a program is launched and loaded into memory and binding occurs at run time. Dynamic or shared libraries can further be categorized into: