C# Language Specifications

The C# language has two major sources of specifications: ECMA and Microsoft. The ECMA specification only goes as far as C# 2.0, even though it's the fourth edition, confusingly enough. This page is a collection of all the versions I've found - but it's quite possible that some will move around, so please let me know if you have any problems, or find any more.

Microsoft specifications

• C# 4.0 (2010; Word document; also available as HTML)
• C# 3.0 (unified, 2007; Word document)
• C# 2.0 (September 2005; Word document)
• C# 1.2 (2003; Word document)
• C# 1.0 (2002; Word document)

The C# 5 specification is not available for download at the time of this writing, but if you have Visual Studio 2012 installed, you can find it under the installation directory (e.g. "C:\Program Files (x86)\Microsoft Visual Studio 11.0") in a subdirectory of "VC#\Specifications\1033".

I can strongly recommend the hard-copy annotated version of the C# 4 specification - I have two copies (one at work and one at home) and I find them very useful. The annotations are really helpful, above and beyond just having a physical version of the specification.

ECMA specifications

• Latest contents: - Fourth edition (June 2006; PDF)
• Archives of old editions:
  • Third edition (June 2005; PDF)
  • Second edition (December 2002; PDF)
  • First edition (December 2001; PDF)

Annotated specifications

Both the ECMA and Microsoft teams have produced annotated specifications, with interesting comments from the design team and some members of the community. I can thoroughly recommend them as providing extra insight. (Disclaimer: I contributed annotations to the ECMA C# 2 and Microsoft C# 4 specs.)

• Microsoft (C# 4) (due out in November 2010)
• Microsoft (C# 3)
• ECMA (C# 2)