Syntax Question - meaning of tilde (~)

I have been learning about the AsyncOperation class and came across this
code (sorry I got it a few days ago and don't remember the specific link).

Anyway, I am wondering what the tilde (~) on line 12 does or what it means.
I've been using C# for a while and somehow haven't encountered the tilde
yet.

Thanks.

1. namespace System.ComponentModel
2. {
3. public sealed class AsyncOperation
4. {
5. internal AsyncOperation (SynchronizationContext ctx, object state)
6. {
7. this.ctx = ctx;
8. this.state = state;
9. ctx.OperationStarted ();
10. }
11.
12. ~AsyncOperation ()
13. {
14. if (!done && ctx != null)
15. ctx.OperationCompleted ();
16. }
//remaining code omitted

--------------- END OF OP ----------------------

re: Syntax Question - meaning of tilde (~)

It means destructor (the same as C++).

WJ

"Frankie" wrote:

re: Syntax Question - meaning of tilde (~)

WJ wrote:No, it doesn't.

It declares the _finalizer_ which is not exactly the same as a C++
destructor.

re: Syntax Question - meaning of tilde (~)

It's the syntax to define a finalizer method. It compiles to a method
that overrides Object.Finalize(). The syntax is the same as for
destructors in C++.


Mattias

--
Mattias Sjögren [C# MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

re: Syntax Question - meaning of tilde (~)

It's default destructor of this class,
yes, C# also has something which is called destructors.
You can TRY to use this feature, by typing Object.Finalize();

On Sep 14, 11:16 pm, "Frankie" <A...@B.COMwrote:

re: Syntax Question - meaning of tilde (~)

Peter Duniho wrote:In the two first edition of the C# standard it was named destructor.

In the third edition they renamed it to finalizer.

To my best knowledge they did not change any semantics.

Arne

re: Syntax Question - meaning of tilde (~)

"Arne Vajhøj" <arne@vajhoej.dkwrote in message
news:46eb45c9$0$90271$14726298@news.sunsite.dk...In C#

To call it "the same" as a C++ destructor is not entirely correct, though.
Finalization can be waaaaay different than C++ destruction. <g>



--
Doug Semler, MCPD
a.a. #705, BAAWA. EAC Guardian of the Horn of the IPU (pbuhh).
The answer is 42; DNRC o-
Gur Hfrarg unf orpbzr fb shyy bs penc gurfr qnlf, abbar rira
erpbtavmrf fvzcyr guvatf yvxr ebg13 nalzber. Fnq, vfa'g vg?

re: Syntax Question - meaning of tilde (~)

Doug Semler wrote:I am not sure that anyone claimed that a C# destructor/finalizer has the
same semantics as C++.

I at least interpreted "same" as "same syntax".

Arne

re: Syntax Question - meaning of tilde (~)

"Arne Vajhøj" <arne@vajhoej.dkwrote in message
news:46eb4bf9$0$90273$14726298@news.sunsite.dk...
*You* may have....*BUT* it is important to make sure that the OP understand
that even though it is the same syntax, it is not the same semantics.
Especially if he one were to read this particular message from top to bottom
without context. That's all I'm saying.

Finalizer, destructor....Tomat-oh, Tom-ah-toe. In C#, the semantics what
the function does is completely different than in C++. And that is what is
not "the same"

<g>

--
Doug Semler, MCPD
a.a. #705, BAAWA. EAC Guardian of the Horn of the IPU (pbuhh).
The answer is 42; DNRC o-
Gur Hfrarg unf orpbzr fb shyy bs penc gurfr qnlf, abbar rira
erpbtavmrf fvzcyr guvatf yvxr ebg13 nalzber. Fnq, vfa'g vg?

re: Syntax Question - meaning of tilde (~)

Doug Semler wrote:And the post to which I replied read "It means destructor (the same as
C++)". The word "means" implies "semantics", whether that was intended
or not. That's what semantics is...the _meaning_.

I don't see how any reasonable interpretation infers "syntax" from the
word "means". I talk about "syntax" when I'm discussion how things are
written, and "semantics" when I'm discussion what those things mean.

But regardless, it's very important to understand that a finalizer isn't
a destructor. It's such an important difference, they even changed the
name to make that more clear.

Pete

re: Syntax Question - meaning of tilde (~)

"Peter Duniho" <NpOeStPeAdM@NnOwSlPiAnMk.comwrote in message
news:13emnhkp6r4el73@corp.supernews.com...
Pete,

I was talking syntax in terms of the original statement. This is the
problem with the English language. Here's two completely different
interpretations of "It [the ~] means destructor (the same as C++)":

1) As in the C++ language, the ~ character in front of the name makes that
the function is a destructor.
2) The ~ character in front of the function name makes the function act as a
destructor as in the a c++ language.

See how the syntax changes the semantics? In statement 1, the modification
is on the ~ character. In statement 2, the modification is on the word
"destructor". Which one is correct in terms of C#? Semantics and syntax
cannot be divorced from each other. (Which is probably why I like
programming languages better than natural languages)

--
Doug Semler, MCPD
a.a. #705, BAAWA. EAC Guardian of the Horn of the IPU (pbuhh).
The answer is 42; DNRC o-
Gur Hfrarg unf orpbzr fb shyy bs penc gurfr qnlf, abbar rira
erpbtavmrf fvzcyr guvatf yvxr ebg13 nalzber. Fnq, vfa'g vg?

re: Syntax Question - meaning of tilde (~)

Peter Duniho wrote:Tilde is a syntactical element.

If someone ask what ^ means will you tell him that it means XOR or
will you tell him what XOR actually does ?

Arne