On 24/01/2013 09:46, Dale wrote:
Neil Bothwick wrote:
On Thu, 24 Jan 2013 03:17:06 -0600, Dale wrote:
<snip>
Why do you say that -N will compile packages that don't need it? If a
USE flags is added, changed or whatever, I want that change to be seen
and the package to be recompiled. It could very well affect how the
package works or some feature.
There are various situations in which it can indeed be a waste of time.
For example, running emerge -auDN @world prompts me to rebuild gcc:
[ebuild R ] sys-devel/gcc-4.6.3 USE="(-go%)"
Why? Because the toolchain eclass was recently modified to better
support the Go programming language. But wait! I didn't have the "go"
flag enabled before because it didn't exist. Nor will it be enabled in
the prospective rebuild. What's more, I couldn't enable it even if I
wanted to because it's masked for this version of gcc (as indicated by
the parentheses).
The upshot is that rebuilding gcc now would serve absolutely no purpose.
The --changed-use parameter understands this whereas -N does not.
Cheers,
--Kerin
