From: Rene Rivera [mailto:grafik.list@redshift-software.com] Rob Stewart wrote:

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From: Rene Rivera <grafik.list@redshift-software.com>

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Gennaro Prota wrote:

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On Sat, 27 Mar 2004 19:23:50 -0500, David Abrahams <dave@boost-consulting.com> wrote:

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"Klaus Nowikow" <nowikow@decomsys.com> writes:

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Reece Dunn wrote: [snip]

> class errorcheck > {

[snip]

> public: > inline errorcheck( int ec ): error( ec ) > { > if( ec < 0 ) throw( *this ); > }

Careful. Throwing an exception from a constructor means that the object won't be constructed (i. e., does not exist). So you are throwing a non-existing object here.

Or am I wrong?

You're wrong. *this is copied before it is thrown. Still, the idiom above seems a bit suspicious, unless you somehow prevent derivation

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from errorcheck.

I can't believe you are justifying the above. You copy an object that doesn't exist yet! (The class is not a POD and has a non trivial constructor - and even if this wasn't the case...)

I don't see how the object is not fully initialized inside its constructor?? Could you explain your objection?

Until the ctor finishes -- after the closing } -- there is no object (see 3.8/1).

Yes the object lifetime hasn't started... but the object is initialized. Which according to 12.7 allows for referring to members of the object directly or indirectly, in this case by a copy ctor function.

I think you are right. When I posted the message above, I didn't take into consideration that the object (*this) is copied before it is thrown. Best regards, Klaus