Creating and Using Shared Libraries in Linux C Programming

Shared libraries are an essential part of Linux C programming. They allow developers to create reusable code that can be shared among multiple programs. Shared libraries not only save time and effort in coding, but they also save memory and disk space. In this post, we will discuss how to create and use shared libraries in Linux C programming.

What are Shared Libraries?

Shared libraries are collections of code that can be used by multiple programs. They contain functions and other code that can be loaded into memory when a program needs it. Shared libraries are also known as dynamic-link libraries or shared objects. They have the extension .so in Linux.

Creating Shared Libraries

Creating a shared library involves several steps. First, we need to create the source code for our library. The code needs to have a standard format for creating shared libraries. Here is an example code:

#include <stdio.h>

void printHello()
{
    printf("Hello, World!\n");
}

The printHello() function is a simple example code that we will use to create our shared library. Now, we compile and link this code using the following command:

gcc -shared -o libhello.so hello.c

The -shared option specifies that we want to create a shared library. The -o option specifies the name of the output file, which is libhello.so. It is a convention to use a prefix lib in the name of the library, followed by the name of the library and an extension .so.

Using Shared Libraries

Once we have created our shared library, we can use it in our program. We need to include the header files for the functions we want to use in our program. Here is an example code:

#include <stdio.h>
#include "hello.h"

int main()
{
    printHello();
    return 0;
}

The #include "hello.h" directive includes the header file that contains the declaration of the printHello() function. We compile and link this program using the following command:

gcc -o hello main.c -L. -lhello

The -L. option specifies the directory where the shared library is located, and the -lhello option specifies the name of the library without the extension.

Conclusion

Creating and using shared libraries in Linux C programming can save developers time, effort, and resources. Shared libraries allow for the reuse of code, resulting in more efficient programming. In this post, we have discussed how to create and use shared libraries in Linux C programming. With these skills, developers can create and share their code, resulting in a more collaborative and efficient development process.

linux  c programming  shared libraries 

See also