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Historically, libraries could only be static. They are usually faster than the shared libraries because a set of commonly used object files is put into a single library executable file….Shared Libraries :
| properties | Static library | Shared library |
|---|---|---|
| Means | Performed by linkers | Performed by operating System |
A shared library can be accessed through different names :
- Name used by linker (‘lib’ followed by the library name, followed by ‘. so’ .
- Fully qualified name or soname ( ‘lib’ followed by the library name, followed by ‘. so’, followed by ‘.
- Real name (‘lib’ followed by the library name, followed by ‘.
What is the purpose of a shared library?
What Are Shared Libraries? A library is a file that contains compiled code and data. Libraries in general are useful because they allow for fast compilation times (you don’t have to compile all sources of your dependencies when compiling your application) and modular development process.
Locating Shared Libraries in Linux. Shared libraries are loaded by ld.so (or ld.so.x) and ld-linux.so (or ld-linux.so.x) programs, where x is the version. In Linux, /lib/ld-linux.so.x searches and loads all shared libraries used by a program. A program can call a library using its library name or filename, and a library path stores directories
If there is any bug in library code, entire application need to be recompiled and shipped to the client. In case of dynamic libraries, fixing or upgrading the libraries is easy. You just need to ship the updated shared libraries. The application need not to recompile, it only need to re-run.
How are shared libraries used in microservices applications?
In the application context, sharing means writing code that is compiled against, and requires at runtime, the same library code as another application. By way of example, two applications may both use the same logging library. They may be deployed on separate hosts residing on opposite sides of the globe, but they “share” this library.