Re: Friend operators don't work where class member operators do.
Historically (some twenty years ago), C++ did allow binding a
temporary to a non-const reference (and many compilers still
allow it today, as a non-conformant extension). It was found,
however, to be somewhat error prone, in cases like e.g.:
void
incr( int& i )
{
++ i ; // Obviously something more complex in real
// code.
}
void
f()
{
unsigned x = 0 ;
incr( x ) ;
}
In this case, the temporary is the result of an implicit
conversion, and the author is very surprised that the call to
incr doesn't modify x.
So I infer that for making a unsigned to int conversion, C++ creates a
new temporary variable and copies the bits instead of the classical C
behaviour that is doing nothing and understanding the bits of x as bits
representing integers. Am I right?. With that behaviour it seems to me
that C++ code would take more time to execute if I have conversions of
that kind in my code.
On the other side, wouldn't it be better not to create temporaries for
the conversion and allow the code you wrote above to be correct and
execute giving correct results?
Otherwise, you should modify "f" function like this:
f()
{
unsigned x = 0 ;
int y=x;
incr( y ) ;
x=y;
}
Regards,
C?sar.
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