Cough, COFF. (Dynamic-loading question)

[Rodian Paul]

I finaly decided to start reading my "Understanding COFF" book by
O'Reilly & Associates last week. I found parts to be heavy wading, but
decided to plug in their example listings and see what I might learn.

The book points out that there are bound to be implementation specific
changes/deviations, but the overall COFF structure should be pretty
standard. Well, I guess MIPS does diverge more than a little. So I 
perused the SGI manuals, and the only one that I could find that really 
deals with object formats is the Assembly Programmers manual. Not being 
well versed in assembley language, my spirits sagged, thus this e-mail.

What I'm particularly interested in is dynamic-loading, i.e. while
a program is executing it can run off, compile and/or link an
object back into itself, fork and continue running with the extra
baggage.

This technique would be nice to implement and use in a manner that is
used by some Macintosh utilities. Adobe Photoshop and others allow a 
user to write their own "plug-in" image processing or different file 
reading/writing filters.

An educated user could be supplied with some templates, they then add 
their own "plug-in's" to a commercial IRIS application, without the 
need to supply additional libraries. It could also make the process of 
customization a lot simpler. Anyway, it's something I'd like to mess with.

I've heard in the past that under Sys V 3.2, dynamic-loading is a real
bitch, but with Sys V 4.0, they've made it much easier. I don't know
how much truth there is in that and I realize that it will probably take 
a while before SGI brings out an IRIX release based on V 4.0.

The 99 Yen question? Would some kind soul who has allready figured out 
dynamic-loading on the SGI/MIPS platform please send me some example code?  
There seems to be enough support routines ( r.e ldfcn() etc. ) but I can't 
find any examples in the SGI manuals. Failing source listings, references to 
any books with examples that don't diverge from the MIPS platform too much 
would be appreciated just as strongly.

Thanks.
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