Avoid collisions between parallel installations of Cygwin

Dave Korn dave.korn.cygwin@googlemail.com
Tue Oct 20 15:00:00 GMT 2009


Corinna Vinschen wrote:

> Actually I think we can make it even more simple.  Assume we start with
> a single USHORT value, which is what we're planning, and two versions
> later we add a ULONG value.  After a successful call to FindResource(),Cygcheck can ask for SizeofResource ().  The size of the resource is a simple
> way to figure out which data is available in that version of the Cygwin
> DLL.

  Maybe, but IMO it's a false economy to *ever* not include a version number
in a public structure like that.  How many times has it caused trouble, as
compared to how many times saving a couple of bytes has been worth it?  What
if we wanted to change just the layout or semantics of a data item, I guess
we'd be obliged to add a new dummy item just to change the size?  The size of
the struct is a one-dimensional and lossy approximation of what's actually in it.

    cheers,
      DaveK



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