How Do Linkers Create Executable Files from Object Code?

What Linkers Do: Resolving References and Building Executables

When converting source code into executable binaries, compilers play a crucial role in translating the code into byte code, also known as object code. However, linkers perform a fundamental task that brings these object files together into a single executable.

Linkers resolve references between object files and external libraries. They identify which external functions and variables are required by the program and incorporate them into the executable. For instance, consider a simple C program that uses the printf function to print a message to the screen.

During compilation, the compiler creates an object file containing a reference to the printf function. The linker then locates the implementation of printf in the standard library and combines it with the object file, generating a complete executable.

Linkers also handle inter-dependency between object files. Complex programs often consist of multiple object files, each containing code that can be referenced by other files. The linker resolves these dependencies by "copying" the necessary functions and libraries into a single executable.

In summary, linkers are essential tools that resolve references between object files and external libraries, ensuring that all necessary code is included in the executable. This process enables the construction of functional and executable programs from multiple pieces of compiled code.

The above is the detailed content of How Do Linkers Create Executable Files from Object Code?. For more information, please follow other related articles on the PHP Chinese website!