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Common Language Infrastructure (CLI)

Short Introduction​

CLI is the open specification that describes the executable code and runtime environment that allows multiple high-level languages to be used on different computer platforms.

Official Definition​

The Common Language Infrastructure (CLI) is an open specification developed by Microsoft that describes executable code and a runtime environment that allows multiple high-level languages to be used on different computer platforms without being rewritten for specific architectures.

Usage​

Key components:

  • Common Type System (CTS)
  • Common Language Specification (CLS)
  • Virtual Execution System (VES)
  • Metadata system

Use Cases​

  • Cross-language interoperability
  • Platform independence
  • Code sharing between different .NET languages

Sample Usage​

// C# code
public class Calculator
{
    public int Add(int a, int b) => a + b;
}
' VB.NET code using the same CLI
Public Class Calculator
    Public Function Add(a As Integer, b As Integer) As Integer
        Return a + b
    End Function
End Class