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From: rsanders@interbev.mindspring.com (Robert Sanders)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: Dynloading and FBSD2.?
Date: 06 Jun 1995 11:30:07 -0400
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Message-ID: <87zqjv4ghs.fsf@interbev.mindspring.com>
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In-reply-to: witr@rwwa.com's message of 6 Jun 1995 14:17:12 GMT
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On 6 Jun 1995 14:17:12 GMT, witr@rwwa.com (Robert Withrow) said:
> But I would sure like to know how I am *supposed* to do it on
> FBSD 2.0R, cause it ain't in the docs, and there ain't a .h file
> for it...
I don't have a 2.0R system around, but 'man dlopen' on 2.0.5A gave a
pretty good description. link(5) and ld(1) are also useful pages to
examine.
FreeBSD's dynamic loading interface is almost identical to the one
you'd use on SunOS. I think the magic procedure for creating a shared
library looks a bit like this (I've only done it under Linux):
gcc -fpic -c foo.c
ld -Bshareable -o libfoo.so.1 foo.o
You can then link against libfoo with -lfoo just as you would against
any other library. In addition, you can use dlopen() to access its
symbols at runtime. If you want real-life examples of building shared
libraries, check out the FreeBSD /usr/lib source tree on an archive
near you.
Under Linux, you have to specify a "-rdynamic" flag to gcc for
executables that were going to use the dl*() routines. That forced to
keep all the executable's externally visible symbols listed in the ELF
symtab. I'm not sure what the equivalent is -- if there is any --
under FreeBSD.
-- Robert