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From: Jan Grant <Jan.Grant@bristol.ac.uk>
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Cc: freebsd-questions <freebsd-questions@freebsd.org>
Subject: Re: portupgrade -ar (why?)
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On Sat, 15 Oct 2005, Peter Matulis wrote:

> What is the use of specifying the 'r' switch when using the 'a'
> switch?
> 
> # portupgrade -ar
> 
> This says to upgrade all ports plus the ones that depend on all
> those ports.  Am I missing something?  Wouldn't "the ones that
> depend" be upgraded anyway?

Not necessarily. For instance: package P might use library L. A change 
in L might alter the size and layout of structures exposed to P. The 
source-level API of L is unchanged; the binary-level ABI is altered. So 
whilst the source code of P might not have changed, it might (for 
instance) be using a macro defined by a header in L that will look at 
the wrong offset in the new structure. These kinds of ABI compatibility 
problems can be fixed by recompilihng P.


-- 
jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
Tel +44 (0)117 3317661   http://ioctl.org/jan/
Strive to live every day as though it was last Wednesday.