C# 5

Book Review: Async in C# 5.0

By jonskeet

Resources: Amazon, Barnes and Noble, Play Books The book’s web site (O’Reilly) – downloads, errata etc A while ago I was attending one of the Developer, Developer, Developer conference in Reading, and I heard Alex Davies give a talk about actors and async. He mentioned that he was in the process of writing a short book for O’Reilly about async in C# 5, and I offered to review it for him. Many months later (sorry Alex!) I’m finally getting round to it. Disclaimer: The review copy was given to me for free, and equally the book is arguably a competitor … Continue reading Book Review: Async in C# 5.0

The future of "C# in Depth"

By jonskeet

I’m getting fairly frequent questions – mostly on Twitter – about whether there’s going to be a third edition of C# in Depth. I figure it’s worth answering it once in some detail rather than repeatedly in 140 characters 😉 I’m currently writing a couple of new chapters covering the new features in C# 5 – primarily async, of course. The current "plan" is that these will be added to the existing 2nd edition to create a 3rd edition. There will be minimal changes to the existing text of the 2nd edition – basically going over the errata and editing … Continue reading The future of "C# in Depth"

Eduasync 20: Changes between the VS11 Preview and the Visual Studio 11 Beta

By jonskeet

A while I ago I blogged about what had changed under the hood of async between the CTP and the VS11 Preview. Well, now that the VS11 Beta is out, it’s time to do it all again… Note that the code in this post is in the Eduasync codebase, under a different solution (Eduasync VS11.sln). Many of the old existing projects won’t compile with VS11 beta, but I’d rather leave them as they are for posterity, showing the evolution of the feature. Stephen Toub has an excellent blog post covering some of this, so while I’ll mention things he’s covered, … Continue reading Eduasync 20: Changes between the VS11 Preview and the Visual Studio 11 Beta

Eduasync part 19: ordering by completion, ahead of time…

By jonskeet

Today’s post involves the MagicOrdering project in source control (project 28). When I wrote part 16 of Eduasync, showing composition in the form of majority voting, one reader mailed me a really interesting suggestion. We don’t really need to wait for any of the tasks to complete on each iteration of the loop – we only need to wait for the next task to complete. Now that sounds impossible – sure, it’s great if we know the completion order of the tasks, but half the point of asynchrony is that many things can be happening at once, and we don’t … Continue reading Eduasync part 19: ordering by completion, ahead of time…

Eduasync part 18: Changes between the Async CTP and the Visual Studio 11 Preview

By jonskeet

In preparation for CodeMash, I’ve been writing some more async code and decompiling it with Reflector. This time I’m using the Visual Studio 11 Developer Preview – the version which installs alongside Visual Studio 2010 under Windows 7. (Don’t ask me about any other features of Visual Studio 11 – I haven’t explored it thoroughly; I’ve really only used it for the C# 5 bits.) There have been quite a few changes since the CTP – they’re not visible changes in terms of code that you’d normally write, but the state machine generated by the C# compiler is reasonably different. … Continue reading Eduasync part 18: Changes between the Async CTP and the Visual Studio 11 Preview

Eduasync part 17: unit testing

By jonskeet

In the last post I showed a method to implement "majority voting" for tasks, allowing a result to become available as soon as possible. At the end, I mentioned that I was reasonably confident that it worked because of the unit tests… but I didn’t show the tests themselves. I felt they deserved their own post, as there’s a bigger point here: it’s possible to unit test async code. At least sometimes. Testing code involving asynchrony is generally a pain. Introducing the exact order of events that you want is awkward, as is managing the threading within tests. With a … Continue reading Eduasync part 17: unit testing

Eduasync part 15: implementing COMEFROM with a horrible hack

By jonskeet

Ages ago when I wrote my previous Eduasync post, I said we’d look at a pipeline model of coroutines. I’ve decided to skip that, as I do want to cover the topic of this post, and I’ve got some more "normal" async ideas to write about too. If you want to look at the pipeline coroutines code, it’s project 20 in the source repository. Have fun, and don’t blame me if you get confused reading it – so do I. The code I am going to write about is horrible too. It’s almost as tricky to understand, and it does … Continue reading Eduasync part 15: implementing COMEFROM with a horrible hack

Speaking engagement: Progressive .NET, London, September 7th

By jonskeet

Just a quick note to mention an event I’ll be speaking at in September. SkillsMatter will be hosting Progressive .NET, a 3-day event set of tutorials on September 5th-7th in London. I’ll be speaking about C# 5’s async feature on the last day (9.30am-1pm) but there’s a host of other speakers too. Should be good. For my own part, with four hours or so to cover async, I should be able to cover both the high level stuff and the implementation details, with plenty of time for the inevitable questions. This one isn’t free though, I’m afraid – it’s normally … Continue reading Speaking engagement: Progressive .NET, London, September 7th

Eduasync part 14: Data passing in coroutines

By jonskeet

(This post covers project 19 in the source code.) Last time we looked at independent coroutines running in a round-robin fashion. This time we’ll keep the round-robin scheduling, but add in the idea of passing data from one coroutine to another. Each coroutine will act on data of the same type, which is necessary for the scheme to work when one coroutine could "drop out" of the chain by returning. Designing the data flow It took me a while to get to the stage where I was happy with the design of how data flowed around these coroutines. I knew … Continue reading Eduasync part 14: Data passing in coroutines

Eduasync part 13: first look at coroutines with async

By jonskeet

(This part covers project 18 in the source code.) As I mentioned in earlier parts, the "awaiting" part of async methods is in no way limited to tasks. So long as we have a suitable GetAwaiter() method which returns a value of a type which in turn has suitable methods on it, the compiler doesn’t really care what’s going on. It’s time to exploit that to implement some form of coroutines in C#. Introduction to coroutines The fundamental idea of coroutines is to have multiple methods executing cooperatively, each of them maintaining their position within the coroutine when they yield … Continue reading Eduasync part 13: first look at coroutines with async