From: "Øyvind Harboe" <oyvind.harboe@zylin.com>
To: Dave Korn <dave.korn@artimi.com>
Cc: binutils@sources.redhat.com
Subject: RE: Referenced symbol not present in final image?
Date: Fri, 08 Apr 2005 12:31:00 -0000 [thread overview]
Message-ID: <1112963445.23080.40.camel@localhost.localdomain> (raw)
In-Reply-To: <SERRANO5y4FypKsEgJX000000bb@SERRANO.CAM.ARTIMI.COM>
> Umm, look, if you really want to know what kind of symbol it is, don't you
> just want to be using "nm" or "objdump --syms" on eh_alloc.o (or libsupc++),
> and it'll probably tell you something interesting like it's weak, or common,
> or somesuch ?
>
> If it's referenced, but doesn't get pulled into the link unless you -U it
> on the linker command line, that suggests that the object that contains it
> is too early in the link order and the objects that reference it are too
> late in the link order, so by the time the linker knows it's needed, it's
> already gone by and be discarded.
The symbol in question is weak, which explains the "strange" behaviour.
Thanks for the tip(s)!
--- a reply I got in mail directly -----
If you define a symbol as weak and do not provide a definition for the
same (as in the example below) then the linker would allow the symbol
to be undefined but still referenced in the binary.
<snip>
#include<stdio.h>
void foo() __attribute__ ((weak));
int main()
{
int c;
if(!c)
foo();
return 0;
}
</snip>
--- a reply I got in mail directly -----
--
Øyvind Harboe
http://www.zylin.com
next prev parent reply other threads:[~2005-04-08 12:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-08 11:14 Øyvind Harboe
2005-04-08 12:17 ` Dave Korn
2005-04-08 12:31 ` Øyvind Harboe [this message]
-- strict thread matches above, loose matches on Subject: below --
2005-04-08 10:30 Øyvind Harboe
2005-04-08 12:23 ` Ravi Ramaseshan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1112963445.23080.40.camel@localhost.localdomain \
--to=oyvind.harboe@zylin.com \
--cc=binutils@sources.redhat.com \
--cc=dave.korn@artimi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).