On Mon, Jan 25, 1999, Jens-Uwe Mager wrote:
> >You're certainly right. But since AIX made such a lot of problems for the DSO
> >support in Apache (you know, every platforms was mostly friendly, except AIX)
> >I really hate this flavor of Unix ;-)
>
> The way DSO's are build under AIX appears to be quite strange, but if
> you look at it you will see that it is really useful. If you throw
> together large components from various folks it is really nice to be
> able to restrict name space problems by explicetely nameing the symbols
> that should be visible from a DSO. Especially if you get to situations
> where a plug-in to an application has its own plug-in system as well
> (for example mod_perl in Apache) you can very quickly encounter
> problems due to name space clashes.
>
> I find the default way of most ELF based systems of simply throwing
> everything in one symbol table a problem for large projects, although
> it is convenient for the lazy ones. And indeed most of the commerical
> Unix vendors have seen the problem as well, and with Sun Solaris, SGI
> and HP-UX you can configure the linkers to produce a similar behaviour
> as in AIX, you only can access what is explicitely specified in an
> export file. We do that in our applications at Helios, and I believe it
> helps us more than it is inconvenient.
Yes, I see the point. And I don't think the support for explicit export lists
isn't useful. It's useful. What's horrible (and what I hate it for) on AIX is
that it _FORCES_ you to use these explicit lists even for small projects like
Apache. You know, we had to do a lot of hacking just for this and we still
have to keep the httpd.exp file in sync with the code just for AIX.
So, let us give credit to IBM for supporting those explicit export lists, but
let us dislike IBM for the fact that they _force_ us to use it even for small
projects like Apache....
Ralf S. Engelschall
[EMAIL PROTECTED]
www.engelschall.com
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