Re: Bizarre linkage problem involving archives

[llewelly]

JoJoTwilligo@hotmail.com (Jo) writes:

> For some reason if I try to link a particular object with a particular
> archive, certain symbols go "undefined", while if I link with the only
> object in the archive, the link succeeds. What it seems to come down
> to, is that an archive isn't just as good as the objects it contains.
> The call goes something like this:
>
> g++ ... -o executable ../mysql_support/libMySQLsupport.a
> ../common/libcommon.a
>
> From this I get a list of:
>
> ../mysql_support/libMySQLsupport.a(_sqlsession.o)(.text+0x1f6): In
> function `_SQLSession::Open(char const*)':
> /home/angus/work_stuff/zedmonitor/mysql_support/_sqlsession.cpp:27:
> undefined reference to `g_Log'
>
> Now, if I put:
>
> g++ ... -o executable ../mysql_support/libMySQLsupport.a
> ../common/parameters_project.o
>
> which should be the same thing, everything links fine. The content of
> ar t ../common/libcommon.a is:
>
> parameters_project.o
>
> So shouldn't ../common/libcommon.a be just as good
> ../common/parameters_project.o?
>
> parameters_project.h has extern Log g_Log; and parameters_project.cpp
> has Log g_Log; which is what I expected to be defined in
> parameters_project.o. Other symbols referenced in _SQLSession (and
> defined in other archives) link fine, and I have other targets in this
> project that link with g_Log without incident. So why is this single
> object unable to link with another single object iff that 2nd object
> is in an archive?

I think  you should cc this to binutils at gnu.org ; this seems more
    down their alley.