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From: j@uriah.heep.sax.de (J Wunsch)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: [Help] Dynamic Link libraries
Date: 25 Oct 1996 22:49:12 GMT
Organization: Private BSD site, Dresden
Lines: 72
Message-ID: <54rg58$9ta@uriah.heep.sax.de>
References: <Dzo4KJ.A96.B.ss1@bath.ac.uk>
Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch)
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ccsmh@bath.ac.uk (Mark Harding) wrote:
> The problem is this: I have a small program that uses the dlopen(),
> dlsym() etc functions to access functions in a Dynamic Library. I can
> get this test program to run under SunOs and Linux but not under FreeBSD.
This is my first attempt to play with this either, but just for fun,
here's what works for me:
j@uriah 809% cat dlib.c
#include <stdio.h>
int
sayhello(void)
{
printf("I'm saying hello only.\n");
return 0;
}
j@uriah 810% cat test.c
#include <dlfcn.h>
int
main(void)
{
void *cookie;
typedef int ext_t (void);
ext_t *sayhello;
if ((cookie = dlopen("shlib.so", 1)) == 0)
return 1;
if ((sayhello = (ext_t *)dlsym(cookie, "_sayhello")) == 0)
return 2;
return sayhello();
}
j@uriah 811% cat Makefile
all: test shlib.so
test: test.o
cc -o test test.o
shlib.so: dlib.o
ld -o shlib.so -Bshareable dlib.o
dlib.o: dlib.c
cc -c dlib.c -fPIC
clean:
rm -f *.o *.so test
j@uriah 812% make
cc -O -c test.c
cc -o test test.o
cc -c dlib.c -fPIC
ld -o shlib.so -Bshareable dlib.o
j@uriah 813% ./test
I'm saying hello only.
j@uriah 814% echo '/saying/s/say/not say/\
? w\
? q' | ed dlib.c
91
95
j@uriah 815% make
cc -c dlib.c -fPIC
ld -o shlib.so -Bshareable dlib.o
j@uriah 816% ./test
I'm not saying hello only.
--
cheers, J"org
joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)