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Neelesh · Guest

Hi all,
I have confusion regarding exact number of called to a CC, since I have
seen compilers "optimizing them". Following program illustrates my
point:

class X{ };

X f()
{
X ret;
return ret;
}

int main()
{
X val = f() ;
}

So the questions are :

1) what is the exact sequence of constructor/CC/dtor in this code?
I state what I believe ie correct -
a) main calls f(). In f() ret is constructed using ctor call.
b) ret is copied to a temporary using a CC call.
c) ret is destroyed as the control reaches end of main.
d) the temporary is copied to val using call to CC of X
e) The temporary is destroyed
f) Finally when control reaches end of main, val is destroyed.

Is this correct?

2) If f() would have been written as

X f()
{
return X(); // Return value optimization
}

then would any temporary be involved? (i.e. would the result of X() be
built into the temporary or directly into 'val'? ) Would the process
involve any call to CC?

3) Is it legal for compilers to "optimize away" these CC calls, if they
can?

Thanks,
Neelesh

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Francis Glassborow · Guest

In article <1130131039.523443.172820 (AT) z14g2000cwz (DOT) googlegroups.com>,
Neelesh <neelesh.bodas (AT) gmail (DOT) com> writes