[Boost-users] [Bind] Placeholders passed by reference?

Subject: [Boost-users] [Bind] Placeholders passed by reference?
From: Robert Jones (robertgbjones_at_[hidden])
Date: 2010-07-06 04:51:37

This works exactly as expected...

void f( unsigned & val ) { val *= 2; }

unsigned i = 3;
boost::bind( f, _1)( i );

with i being doubled. What I don't get is why I don't need to
say

boost::bind( f, boost::ref( _1 ) )( i );

and conversely how I specify that I want bind to pass by value
rather than by reference for the placeholder.

Thanks

- Rob.