[Ns-developers] Extenral Library Dependency

[George Riley]

>
>
>
> In the case of pthreads, you need to link with librt.  One way to do  
> this is
> to add something like,
>
>    variant_env.append_value('LINKFLAGS', '-L/lib -lrt')
Aren't there some systems that require -lpthread?

George
>
>
> in the "def configure(conf):" function of the top-level wscript.   
> That seems
> to be a brute force and awkwardness approach, though.  There's got  
> to be a
> better way.
>
> It would be nice to be able to add the dependency at the module  
> level in
> this case.  For example, to be able to tell the core wscript that  
> core now
> needs to be linked against librt.  I found something called "uselib"  
> that
> seems to do something like that but I haven't had any success in  
> applying
> this.
>
> Another case I'm pondering is a device that might need to link against
> libpcap.  Again, it would not be very clever to add a dependency on  
> pcap to
> the whole system when many folks will never use the device in  
> question.  It
> would be nice to be able to tell the wscript in src/devices/x that  
> code
> linking against this device needs also to link libpcap; and only  
> actually
> resolve references if a script needs to use the 'x' device.
>
> This brings me to yet another point.  Since we started monolithically
> linking into a gargantuan libns-3 library, we seem to have lost  
> track of how
> we need to specify dependencies in the wscripts.
>
> It used to be the case that we had to explicitly add libraries as in,
>
>    obj = bld.create_ns3_program('wifi-adhoc',
>        ['core', 'simulator', 'mobility', 'wifi'])
>
> but now, I believe that
>
>    obj = bld.create_ns3_program('wifi-adhoc')
>
> works just as well; and some examples seem to have incomplete lists of
> module dependencies.
>
> Anyway, I'm not sure how this should all play out, and where the
> declarations of library dependencies should actually go and whether  
> or not
> the lists in wscripts are meaningful.  Can one of you waf guru-types  
> give me
> a hand doing this in a sane way?
>
> Thanks,
>
> -- Craig
>
>