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Hi all:

I have a class with a method that throws an exception.

class A {
public:
void myMethod() throw(MyException);
};

My question is if MyExcepcion must be defined at that point or not.
I think it must because if I use a forward declaration of MyExcepcion,
compiler gives me an error.

Is there any valid way without include the definition of MyException
before A?

Thanks in advance

"Carlos Martinez Garcia" <> wrote in message
news:dob87q$...
> Hi all:
>
> I have a class with a method that throws an exception.
>

class MyException;

> class A {
> public:
> void myMethod() throw(MyException);
> };
>
> My question is if MyExcepcion must be defined at that point or not.
> I think it must because if I use a forward declaration of MyExcepcion,
> compiler gives me an error.
>
> Is there any valid way without include the definition of MyException
> before A?
>
> Thanks in advance

Jim Langston wrote:
> class MyException;

Isn't the definition also necessary?
The following code fails to compile (g++3.4.2, Comeau)

class MyException;
class A {
public:
void myMethod() throw(MyException);
};

Carlos Martinez Garcia wrote:
> Hi all:
>
> I have a class with a method that throws an exception.
>
> class A {
> public:
> void myMethod() throw(MyException);
> };
>
> My question is if MyExcepcion must be defined at that point or not.
> I think it must because if I use a forward declaration of MyExcepcion,
> compiler gives me an error.

The definition is necessary.

> Is there any valid way without include the definition of MyException
> before A?

Declare a function that throws the exception and use that function
isntead of throw statement.

extern void throw_my_exception();

// void myMethod() throw(MyException);
void myMethod() { throw_my_exception(); }

Maxim Yegorushkin wrote:
> Carlos Martinez Garcia wrote:
> Declare a function that throws the exception and use that function
> isntead of throw statement.
>
> extern void throw_my_exception();
>
> // void myMethod() throw(MyException);
> void myMethod() { throw_my_exception(); }

The OP's original code was using an exception specification, not
necessarily throwing an exception. Your code isn't evuivalent.

I nearly made the same mistake since I never see exception
specifications in the real world.

Gavin Deane

wrote:

[]

> The OP's original code was using an exception specification, not
> necessarily throwing an exception. Your code isn't evuivalent.

Sorry, my mistake.

Carlos Martinez Garcia wrote:
> Hi all:
>
> I have a class with a method that throws an exception.
>
> class A {
> public:
> void myMethod() throw(MyException);
> };
>
> My question is if MyExcepcion must be defined at that point or not.
> I think it must because if I use a forward declaration of MyExcepcion,
> compiler gives me an error.
>
> Is there any valid way without include the definition of MyException
> before A?
>
> Thanks in advance

The experts suggest not using exception specifications at all. See
these links:

http://www.gotw.ca/publications/mill22.htm

http://www.gotw.ca/gotw/082.htm

A quote from the first:

"So here's what seems to be the best advice we as a community have
learned as of today:
"Moral #1: Never write an exception specification.
"Moral #2: Except possibly an empty one, but if I were you I'd
avoid even that."

Not using such specs would likely eliminate your problem.

Cheers! --M

mlimber <> wrote:

> The experts suggest not using exception specifications at all. See
> these links:

> http://www.gotw.ca/publications/mill22.htm

That's a very informative article. Thanks for posting it. Does it
reflect the consensus of c.l.c++ posters, do you think?

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cyberspace.org | don't, I need to know. Flames welcome.

Christopher Benson-Manica wrote:
> mlimber <> wrote:
>
> > The experts suggest not using exception specifications at all. See
> > these links:
>
> > http://www.gotw.ca/publications/mill22.htm
>
> That's a very informative article. Thanks for posting it. Does it
> reflect the consensus of c.l.c++ posters, do you think?

It does.

Cheers! --M

Christopher Benson-Manica <> wrote:
> mlimber <> wrote:
>
>> The experts suggest not using exception specifications at all. See
>> these links:
>
>> http://www.gotw.ca/publications/mill22.htm
>
> That's a very informative article. Thanks for posting it. Does it
> reflect the consensus of c.l.c++ posters, do you think?

As far as I have seen, yes. It probably also doesn't help that a
popular compiler (MS's) doesn't even handle std::unexpected properly
(see
http://msdn.microsoft.com/library/de...deep111899.asp
(and the next article also, Part 12) for an explanation; it is an MSDN
site but most of the article refers to standard C++).

--
Marcus Kwok