Re: bind2nd (and bind1st) wasting a copy ?
On 22 Jun, 03:12, Vincent Poinot <clcppm-pos...@this.is.invalid>
wrote:
Reading the code of several STL implementations, I noticed that bind2nd is
always implemented like this:
template <class _Operation, class _Tp>
inline binder2nd<_Operation>
bind2nd(const _Operation& __fn, const _Tp& __x)
{
typedef typename _Operation::second_argument_type _Arg2_type;
return binder2nd<_Operation>(__fn, _Arg2_type(__x));
}
I find it strange that no matter what _Tp is, the function first performs
a
copy of __x to turn it into an _Arg2_type, creating a temporary that will
then be copied by the constructor of binder2nd, and destroyed just after.
It seems to me that if _Tp is _Arg2_type, we could very well avoid this
extra copy (and destruction), hence cutting the processing time of bind2nd
by half considering that it essentially stores the value __x in a new
function object.
[]
Could you provide results of profiling your hypothesis please?
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