This will always cause one box operation. The version of WriteLine that will be called will be the one with the signature
WriteLine(string format, params object[] args); Therefore all the args will be treated as object - this means the 1 will be boxed. However, the second argument due to operator precedence will create the struct, and call its ToString method. The compiler knows exactly which ToString method must be called - if MyStruct overrides ToString then it will be the MyStruct version if not it will be System.Object's version - therefore, no virtual dispatch is required and therefore no boxing. Regards Richard Blewett - DevelopMentor > -----Original Message----- > From: Discussion of advanced .NET topics. [mailto:ADVANCED- > [EMAIL PROTECTED] On Behalf Of Igal Yoffe > Sent: 07 August 2007 08:20 > To: ADVANCED-DOTNET@DISCUSS.DEVELOP.COM > Subject: [ADVANCED-DOTNET] compiler considerations > > Consider the following code: > Console.Writeline("{0} {2}",1,(new MyStruct()).ToString()); > > The number of boxings in such code is between 0 to 2, depending on the > implementation of the compiler. > > Straightforwardly, two boxings are obvious, viz., int boxing and > struct's > boxing before calling ToString. However, it could be the case that in > compile time the compiler creates "object(1)" (really a trivial > optimization) for the integer, and moreover have special vtable logic > for > structures (recall that structures could not be inherited) which calls > ToString directly, thus no boxings at all. > > While I could examine the ilasm generated by _my_ compiler I would be > really glad to know what do you think _typical_ (e.g. microsoft's csc) > compiler would do? > > =================================== > This list is hosted by DevelopMentorR http://www.develop.com > > View archives and manage your subscription(s) at > http://discuss.develop.com =================================== This list is hosted by DevelopMentor® http://www.develop.com View archives and manage your subscription(s) at http://discuss.develop.com
