[clue-tech] Forcing gcc compiler to link against specific so

[Jim Ockers]

Hi Marcus,

Thanks!

> On Thu, Jan 05, 2006 at 06:16:39PM -0700, Jim Ockers wrote:
> > Hi,
> > 
> > Does anyone know how to force the linker/dynamic loader to use a
> > specific (older) version of a library when two versions are present
> > on the compiler system?
> > 
> > We compile an application that has -lcrypto in the compiler/linker
> > command line.  It is dynamically linked.  The development systems
> > have these libcrypto:
> > 
> > -rwxr-xr-x    1 root     root       918752 Sep  7  2001 /lib/libcrypto.so.0.9.6b
> > -rwxr-xr-x    1 root     root      1118600 Mar 11  2005 /lib/libcrypto.so.0.9.7a
> > lrwxrwxrwx    1 root     root           19 Jun 14  2004 /lib/libcrypto.so.2 -> libcrypto.so.0.9.6b
> > lrwxrwxrwx    1 root     root           19 Jun 20  2005 /lib/libcrypto.so.4 -> libcrypto.so.0.9.7a
> > 
> > Our application would link just fine against libcrypto.so.2 but
> > because libcrypto.so.4 is present on the system (and needed for
> > a different application) this application always links against
> > libcrypto.so.4 .
> 
> One way to do this is instead of "-lcrypto", use "/lib/libcrypto.so.2".
> Another way is to create a directory with a symlink
> 
> dumylib:
> 	libcrypto.so -> /lib/libcrypto.so.2
> 
> Then, use "-Ldumylib -lcrypto".

Hey, this works perfectly.  Now our application is linked against these
libraries:

        libsqlplus.so.1 => /usr/lib/libsqlplus.so.1 (0x40033000)
        libz.so.1 => /usr/lib/libz.so.1 (0x400a2000)
        libcrypto.so.2 => /lib/libcrypto.so.2 (0x400b0000)
        libdl.so.2 => /lib/libdl.so.2 (0x40173000)
        libstdc++-libc6.2-2.so.3 => /usr/lib/libstdc++-libc6.2-2.so.3 (0x40177000)
        libm.so.6 => /lib/i686/libm.so.6 (0x401b9000)
        libc.so.6 => /lib/i686/libc.so.6 (0x401dd000)
        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)

As you can see libcrypto.so.4 is nowhere to be found.  OutSTANDing!
Thanks again.

I wonder why my google searches didn't turn anything up about this? Hm!

-- 
Jim Ockers, P.Eng. (ockers at ockers.net)
Contact info: please see http://www.ockers.net/
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