On Wed, 2009-08-19 at 18:20 -0400, Chuck Lever wrote:

On Aug 19, 2009, at 4:44 PM, Joe Perches wrote:

quoted

I'm not too sure there's much value in ever more formatters for
relatively simple things or in printing something like port or
scope without the ip address.

%hu ntohs(sa6->sin6_port)
or
%d or 0x%x ntohl(sa6->sin6_flowinfo)

seem pretty straightforward to me.

It's the same issue for port numbers as it is for addresses: though  
the port field is the same size in each, it's at different offsets in  
AF_INET and AF_INET6 addresses, so extra logic is still needed to sort  
that at each call site.

As an example, an rpcbind query cares about the port number result,  
but usually not the address.  A human-readable message could show the  
returned port number, but leave out the address.  Without a separate  
formatter, you would still need extra logic around each debugging  
message (for example) to choose how to print the port number.

You could probably argue, though, that this is a less common need than  
printing addresses.

I suppose an address exclude could be added to %pN
if really needed.  Maybe "%pNx(specifiers)"

quoted

Here's another tentative patch that does both using square
brackets around IPv6 addresses with a port number and
allows selection of the port number style ":dddd" or ":hi.lo"

The "hi.lo" form is always separated from the address by a dot, not by  
a colon, and square brackets are never used in that case.  The hi.lo  
format is probably enough of a special case that a separate specifier  
for that one is unnecessary.

Is the RPC code never used with a ipv6_addr_v4mapped address?
::192.168.0.1.1.1 would look pretty ugly

Having a hexadecimal port number option  
might be more useful.  The hexadecimal form is also used by the  
kernel's RPC implementation, fwiw.

Easy enough. %pNhp or some such.

quoted

It also adds a "pI6n" form for IPv6 addresses with 7 colons
and no leading 0's.

What would the 7 colons form be used for?

Shorter output requiring colon parsing, no :: parsing.
It's easier for humans to visually scan than the
leading 0 form.