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From: Dan <drose@dtlm.homelinux.net>
To: gentoo-user@lists.gentoo.org
Subject: [gentoo-user] OT -- gcc .o linking and undefined references
Date: Sun, 23 Oct 2005 13:20:52 +1000	[thread overview]
Message-ID: <435B0194.4090509@dtlm.homelinux.net> (raw)

Hi everyone, I'm doing something really obviously wrong, but I don't 
know what.

I can gcc -c -o file.o file.c  and get a binary object.

I do this for the main and two "helper" .c files

This works, then I get a bunch of .o files.

then you usually do

gcc -o <final executable name> <main.o> <myfile1.o> <myfile2.o>

and gcc does the linking.

In thsi case, myfile2.c uses ldap_init and ldap_simple_bind, and 
myfile2.h inludes ldap.h.

At this point, there is no ldap.o, just the ldap.h from 
/usr/include/ldap.h so compile of everything stalls, saying that there 
is an undefined reference to the function ldap_init and ldap_simple_bind.

Testing indicates that you can do:

int main() {
thingy_do(123);
}

and it will happily do a gcc -c -o main main.c  and create the object, 
which is what it should -- it's not until we link .o's to create a real 
executable that the system wants to make sure the executable code exists.

The bit that makes me think I'm stupid is that it seems that neither gcc 
or I can find the source (.c) or compiled binaries (.o) which implement 
the structures and functions defined in ldap.h.  What am I doing wrong?  
Where are the .c and .o files supposed to be on a regular linux system? 
Where on gentoo? Have I missed a crucial flag?

Thanks in advance...

-- 
gentoo-user@gentoo.org mailing list



             reply	other threads:[~2005-10-24 10:22 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-10-23  3:20 Dan [this message]
2005-10-24  8:41 ` [gentoo-user] OT -- gcc .o linking and undefined references Christoph Gysin

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