Do string literals get optimised by the compiler?

Question

Does the C# compiler or .NET CLR do any clever memory optimisation of string literals/constants? I could swear I\'d heard of the concept of \"string internalisation\" so th

Answer 1

This article explains string interning pretty well. Quote:

.NET has the concept of an "intern pool". It's basically just a set of strings, but it makes sure that every time you reference the same string literal, you get a reference to the same string. This is probably language-dependent, but it's certainly true in C# and VB.NET, and I'd be very surprised to see a language it didn't hold for, as IL makes it very easy to do (probably easier than failing to intern literals). As well as literals being automatically interned, you can intern strings manually with the Intern method, and check whether or not there is already an interned string with the same character sequence in the pool using the IsInterned method. This somewhat unintuitively returns a string rather than a boolean - if an equal string is in the pool, a reference to that string is returned. Otherwise, null is returned. Likewise, the Intern method returns a reference to an interned string - either the string you passed in if was already in the pool, or a newly created interned string, or an equal string which was already in the pool.