What is Environment.FailFast?

Question

How is it useful?

I think the second part of the question is really the question. Finding out /what/ is a google, why has me stumped. Unless u are doing something really nasty with unsafe code or something... usermode BSOD - for when there is nothing certain any longer and you don't want to risk breaking something. — Fowl, Feb 19 '09 at 10:45
One usage could be when client’s license(subscription) is ended after checking through a webApi. Just ending the application — Daniel B, Jan 21 '20 at 22:59

score 33 · Accepted Answer · edited Dec 18 '20 at 00:55

It is used to kill an application. It's a static method that will instantly kill an application without being caught by any exception blocks.

Environment.FastFail(String) can actually be a great debugging tool. For example, say you have an application that is just downright giving you some weird output. You have no idea why. You know it's wrong, but there are just no exceptions bubbling to the surface to help you out. Well, if you have access to Visual Studio 2005's Debug->Exceptions... menu item, you can actually tell Visual Studio to allow you to see those first chance exceptions. If you don't have that, however you can put Environment.FastFail(String) in an exception, and use deductive reasoning and process of elimination to find out where your problem in.

Reference

Debugger.Launch and Debugger.Break can also be helpful with this kind of scnenario. — Jason Kresowaty, Mar 20 '09 at 22:32
Is there any difference between this and `Process.GetCurrentProcess().Kill()`? — devios1, Aug 10 '10 at 00:23

score 15 · Answer 2 · answered Jan 07 '11 at 19:13

15

It also creates a dump and event viewer entry, which might be useful.

answered Jan 07 '11 at 19:13

Please treat your mods well.

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Axel Rietschin · Answer 3 · 2016-08-09T19:54:46.293

Failfast can be used in situations where you might be endangering the user's data. Say in a database engine, when you detect a corruption of your internal data structures, the only sane course of action is to halt the process as quickly as possible, to avoid writing garbage to the database and risk corrupting it and lose the user's data. This is one possible scenario where failfast is useful.

Another use is to catch programmer errors. Say you are writing a library and some function accepts a pointer that cannot be null in any circumstance, that is, if it's null, you are clearly in presence of a programmer error. You can return an error like E_POINTER or throw some InvalidArgument exception and hope someone notices, but you'll get their attention better by failing fast :-)

Note that I'm not restricting the example to pointers, you can generalize to any parameter or condition that should never happen. Failing fast ultimately results in better quality apps, as many bugs no longer go unnoticed.

Finally, failing fast helps with capturing the state of the process as faithfully as possible (as a memory dump gets created), in particular when failing fast immediately upon detecting an unrecoverable error or a really unexpected condition.

If the process was allowed to continue, say the 'finally' clauses would run or the stack would be unwound, and things would get destroyed or disposed-of, before a memory dump is taken, then the state of the process might be altered in such as way that makes it much more difficult to diagnose the root cause of the problem.

score 7 · Answer 4 · edited Dec 18 '20 at 00:55

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It's a way to immediately exit your application without throwing an exception.

Documentation is here.

Might be useful in some security or data-critical contexts.

edited Dec 18 '20 at 00:55

Pang

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answered Feb 19 '09 at 09:58

Ed Guiness

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Wouldn't it be a concern that it reports data to MS: "and then includes the message in error reporting to Microsoft." – peteski Feb 09 '16 at 10:39

score 5 · Answer 5 · edited Oct 26 '20 at 12:07

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From .NET Framework Design Guidelines on Exception Throwing:

✓ CONSIDER terminating the process by calling System.Environment.FailFast (.NET Framework 2.0 feature) instead of throwing an exception if your code encounters a situation where it is unsafe for further execution.

edited Oct 26 '20 at 12:07

Palec

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answered Apr 04 '16 at 15:48

Teoman shipahi

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score 5 · Answer 6 · answered Jun 11 '09 at 20:12

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It kills the application and even skips try/finally blocks.

answered Jun 11 '09 at 20:12

PRINCESS FLUFF

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score 0 · Answer 7 · answered Jul 08 '19 at 11:02

Joe Duffy discusses failing fast and the discipline to make it useful, here.

http://joeduffyblog.com/2014/10/13/if-youre-going-to-fail-do-it-fast/

Essentially, he's saying that for programming bugs - i.e. unexpected errors that are the fault of the programmer and not the programme user or other inputs or situations that can be reasonable expected to be bad - then deciding to always fail fast for unexpected errors has been seen to improve code quality.

I think since its an optional team decision and discipline, use of this API in C# is rare since in reality we're all mostly writing LoB apps for 12 people in HR or an online shop at best.

So for us, we'd maybe use this when we want deny the consumer of our API the opportunity of making any further moves.

score 0 · Answer 8 · answered Feb 08 '21 at 02:08

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An unhandled exception that is thrown (or rethrown) within a Task won't take effect until the Task is garbage-collected, at some perhaps-random time later.

This method lets you crash the process now -- see this answer.

answered Feb 08 '21 at 02:08

ChrisW

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What is Environment.FailFast?

8 Answers8

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