From:	wemccaug AT prairienet DOT org (Wendy E. McCaughrin)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: no copy-ctor for temps
References:	<37FC2A1A DOT 90EA29A AT a DOT crl DOT com> <37F562D4 DOT 57291365 AT a DOT crl DOT com> <eb8J3.1214$%K6 DOT 36 AT firefly> <aoUK3.214$_9 DOT 60 AT firefly>
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Message-ID:	<zSsN3.588$_9.27@firefly>
Date:	Thu, 14 Oct 1999 22:33:03 GMT
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To:	djgpp AT delorie DOT com
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Reply-To:	djgpp AT delorie DOT com

In a previous article, weiqigao AT a DOT crl DOT com (Weiqi Gao) says:

>"Wendy E. McCaughrin" wrote:
>> 
>> In a previous article, weiqigao AT a DOT crl DOT com (Weiqi Gao) says:
>> 
>> >>    TstCpy(Overflow(" I am a temporary\n"));  // passing temp: no
>> >>                                              // copy-ctor
>> >
>> >The object is constructed on TstCpy()'s stack.
>> 
>> Well ... not exactly :)  I single-stepped through the disassembled
>> code via FSDB and found that the object is ctor'd on main's stack,
>> not on TstCpy's. The argument passed to TstCpy() is always a ptr to
>> the temp, in both calls: that ptr is an address in main's stack-frame.
>
>You are right.  Running it inside gdb reveals that the object is
>constructed inside what gdb described as main's frame.  I guess that's
>dictated by the calling convention.  But logically, the object lives
>with TstCpy().  For example, it is destructed when TstCpy() returns. 
>Also, only TstCpy() can access the object, while main() cannot.
>
>-- 
>Weiqi Gao
>weiqigao AT a DOT crl DOT com
>

 I should have read the info on options more carefully. Apparently, the
 default action of `gpp' is _not_ to invoke the copy ctor in my circum-
 stance (to init a temp), and this seems to be in accordance with the 
 current C++ standard. If one _always_ wants the copy ctor invoked, just 
 specify option: -fno-elide-constructors.

 Thanks for all the help!

 -- Wendy

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