Article · Wikipedia archive · Last revised May 27, 2026

Common Language Runtime

The Common Language Runtime (CLR), the virtual machine component of Microsoft .NET Framework, manages the execution of .NET programs. Just-in-time compilation converts the managed code into machine instructions which are then executed on the CPU of the computer. The CLR provides additional services including memory management, type safety, exception handling, garbage collection, security and thread management. All programs written for the .NET Framework, regardless of programming language, are executed in the CLR. All versions of the .NET Framework include CLR. The CLR team was started June 13, 1998.

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The Common Language Runtime (CLR), the virtual machine component of Microsoft .NET Framework, manages the execution of .NET programs. Just-in-time compilation converts the managed code (compiled intermediate language code) into machine instructions which are then executed on the CPU of the computer.1 The CLR provides additional services including memory management, type safety, exception handling, garbage collection, security and thread management. All programs written for the .NET Framework, regardless of programming language, are executed in the CLR. All versions of the .NET Framework include CLR. The CLR team was started June 13, 1998.

CLR implements the Virtual Execution System (VES) as defined in the Common Language Infrastructure (CLI) standard, initially developed by Microsoft itself. A public standard defines the Common Language Infrastructure specification.2

Overview of the .NET Framework CLR release history1
CLR version .NET version
1.0 1.0
1.1 1.1
2.0 2.0, 3.0, 3.5
4 4, 4.5, 4.6, 4.7, 4.8

During the transition from legacy .NET technologies like the .NET Framework and its proprietary runtime to the community-developed .NET Core, the CLR was dubbed CoreCLR.3 The term CLR today may refer to either the .NET Framework CLR or Core CLR4

Since .NET 5, the runtime for .NET follows a yearly release cadence, releasing a new version every November5

See also

See also

References

References

  1. "Common Language Runtime (CLR)". MSDN Library. Retrieved 14 November 2013.
  2. "ECMA C# and Common Language Infrastructure Standards". Visual Studio Developer Center. Retrieved 14 November 2013.
  3. "Understanding .NET Framework, .NET Core, .NET Standard And Future .NET". www.c-sharpcorner.com. Retrieved February 1, 2021.
  4. ".NET Glossary - CLR". Microsoft Learn. Retrieved October 17, 2025. The exact meaning depends on the context. Common Language Runtime usually refers to the runtime of .NET Framework or the runtime of .NET.
  5. ".NET and .NET Core official support policy". Microsoft .NET Support. Retrieved October 17, 2025. A new major release of .NET is published every year in November...
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