What is type safty in dot net?

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Bhuwan Bhaskar - 20 Oct 2007 05:38 GMT

Hi,

What is type safety in Dot net?

Bhuwan

Reply to this Message

Jon Skeet [C# MVP] - 20 Oct 2007 08:05 GMT

> What is type safety in Dot net?

Well, that's a very broad question. What's the context? What exactly
are you trying to find out?

Signature

Jon Skeet - <skeet@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

Reply to this Message

Scott M. - 20 Oct 2007 14:39 GMT

Essentially, it means that the compiler won't let you treat an apple like a
trampoline.

In other words, the compiler looks at the "type" you are working with in
your statements and makes sure that you only do things with or to that type
that are allowed for that type.

C# has this automatic type-safety built in by defalut. With VB .NET, you
must change the Option Strict setting in Tools...Options to On (the default
is off).

-Scott

> Hi,
>
> What is type safety in Dot net?
>
> Bhuwan

Reply to this Message

Göran Andersson - 21 Oct 2007 09:26 GMT

> Essentially, it means that the compiler won't let you treat an apple like a
> trampoline.
[quoted text clipped - 6 lines]
> must change the Option Strict setting in Tools...Options to On (the default
> is off).

VB.NET is actually type safe regardless of the Option Strict setting.

With the setting off it allows a lot of implicit conversions that is not
allowed in strict mode, but the conversions are still type safe. If the
conversion would produce an unusable result, you get a runtime error
instead.

> -Scott
>
[quoted text clipped - 3 lines]
>>
>> Bhuwan

Signature

Göran Andersson
_____
http://www.guffa.com

Reply to this Message

Scott M. - 21 Oct 2007 21:38 GMT

Well, I think when most folk talk about type-safety, they are referring to
design-time, not run time. After all, with your definition, you could make
the argument that VB .NET is also bug-safe, since you'll get a runtime
exception or runtime anomoly when the program encounters bugs. If there
were such a thing as a bug-safe language, you'd expect it would indicate a
bug as your were creating the bug.

>> Essentially, it means that the compiler won't let you treat an apple like
>> a trampoline.
[quoted text clipped - 21 lines]
>>>
>>> Bhuwan

Reply to this Message

Göran Andersson - 21 Oct 2007 21:55 GMT

> Well, I think when most folk talk about type-safety, they are referring to
> design-time, not run time.

Then they are confused, as that is strong typing, not type safety.

> After all, with your definition,

The definition is not mine.

> you could make
> the argument that VB .NET is also bug-safe, since you'll get a runtime
> exception or runtime anomoly when the program encounters bugs.

Not at all. A bug can very well result in a perfectly normal result,
even if it isn't the correct result.

Signature

Göran Andersson
_____
http://www.guffa.com

Reply to this Message

Bhuwan Bhaskar - 22 Oct 2007 05:32 GMT

Hi Göran,

what are your views for 'type safety' and 'strongly typed' in dot net. I
will be obliged if you make my concept clear on these terms.

Thanks,

Bhuwan

>> Well, I think when most folk talk about type-safety, they are referring
>> to design-time, not run time.
[quoted text clipped - 11 lines]
> Not at all. A bug can very well result in a perfectly normal result, even
> if it isn't the correct result.

Reply to this Message

Göran Andersson - 22 Oct 2007 07:22 GMT

> what are your views for 'type safety' and 'strongly typed' in dot net. I
> will be obliged if you make my concept clear on these terms.

A type safe language won't allow operations or conversions that can give
an illegal result.

For example, converting a Long to an Integer i VB.NET will check that
the value is actually possible to store in an Integer.

A strongly typed language enforces type conversions to be explicit.

For example, with Option Explicit On VB.NET will not implicitly convert
a string to a number, but with Option Explicit Off, it will.

Type safety:
http://en.wikipedia.org/wiki/Type_system#Safely_and_unsafely_typed_systems

Type strength:
http://en.wikipedia.org/wiki/Type_system#Strong_and_weak_typing

Signature

Göran Andersson
_____
http://www.guffa.com

Reply to this Message

Bhuwan Bhaskar - 20 Oct 2007 17:40 GMT

Thanks all !

Bhuwan

> Hi,
>
> What is type safety in Dot net?
>
> Bhuwan

Reply to this Message

Rate this thread:

What is type safty in dot net?

Free Magazines