Linking & Execution

Back to Compiler Design
Arjit Sharma
01 Min

What Is Linking?

Once each part of a program is compiled into machine code (object files), the linker combines these files with libraries (like pre-written code for printf) into a single executable file. It’s like assembling a puzzle, connecting all pieces to make a complete picture.

The linker:

  • Merges multiple object files.
  • Resolves references (e.g., connects printf to its code in the C library).
  • Creates a program you can run.

Types of Linking

  • Static Linking: All code (including libraries) is packaged into one big executable
  • Dynamic Linking: External libraries (like .dll or .so files) are linked at runtime, keeping the executable smaller

What Is Execution?

  1. The OS loads the binary into memory
  2. Sets up a stack (for variables) and heap (for dynamic data)
  3. Initializes registers and jumps to the start point (like main())
  4. The CPU starts executing your instructions
Next →