Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!rice!sun-spots-request
From: chuck@morgan.com (Chuck Ocheret)
Newsgroups: comp.sys.sun
Subject: Re: dynamic loading under SunOS 4.1
Keywords: SunOS
Message-ID: <8316@brazos.Rice.edu>
Date: 30 May 90 14:44:49 GMT
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Organization: Sun-Spots
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X-Refs:  Original: v9n188
X-Sun-Spots-Digest: Volume 9, Issue 188, message 5

> From: uunet!tapir.Caltech.EDU!edelsohn (David Edelsohn)
> 	SunOS 4.1 is suppose to have routines such as dlopen() which should
> provide runtime dynamic linking without /bin/ld -A on static programs.  I
> have not seen the details yet and I am interested in finding out.  The game
> should be to "cc -pic" the subroutines and then map them in with dlopen().
> This should provide user-mode access to the kernel dynamic linking/loading
> facilities which previously required the routine to be in a shared library
> known to the system prior to running the executable image.
> 					David

The thing missing from dlopen() is that it does not resolve symbols in my
.o (pic or not) file (as far as I can find in the manuals).  If I have a
call to printf() in a .o file which I want to dynamically load in after my
process is running, how does printf()'s entry point get resolved with
SUN's shared libraries?  Must I manually look through the .o symbol table
and attempt to find the modules in the various shared libraries?  What
order do I use to search the libraries?  On the man page for dlopen(3),
there is a mention of a -ldl option to ld (I assume this means there is a
libdl.a) which, I suspect, provide routines for accomplishing such binding
(init() and fini()).  However, I cannot find any specific mention of them
anywhere else in SUN's documentation, including the Global Index.

~chuck