Re: libtool zealeousness: how to stip off -pthread added by libtool

[Jerome BENOIT <g6299304p@rezozer.net>]

Hell Russ, thanks for your reply.

On 07/11/14 04:39, Russ Allbery wrote:
> Jerome BENOIT <g6299304p@rezozer.net> writes:
> 
>> for my current packaging, a program that does not use pthread
>> directly is linked against a library that uses (intensively)
>> pthread:  libtool add the option -pthread while is not necessary
>> (and not wanted in my case).
> 
> I'm a little dubious that this is guaranteed to always be the case.
> The reason why libraries that use pthreads heavily export that linker
> flag is that I believe there are some situations where this *does*
> matter and the program needs to be linked with -pthread when it uses
> such libraries, even if it doesn't use pthreads itself.
> 
> I'm not sure if any of those situations occur on Linux, but I would
> be a little dubious about removing this.
> 
>> So I get the following warning message from dpkg-shlibdeps:
> 
>> warning: package could avoid a useless dependency if
>> debian/tachyon-bin-nox/usr/bin/tachyon-nox was not linked against
>> libpthread.so.0 (it uses none of the library's symbols)
> 
> Note that libpthread is included in the libc6 package already, so
> while there's a warning about this, it doesn't create any unnecessary
> package dependencies.  That means this causes essentially zero ill
> effects for your program (in fact, I wonder if libpthread should just
> be whitelisted for this check in dpkg-shlibdeps).  That's
> particularly true since your program is linked with a library that
> uses libpthread, so libpthread is going to be loaded by your program
> anyway.
> 
> In short, I'd just ignore this.  That's what I do in similar
> situations for my packages.

As a matter of fact, tachyon-nox can be build against different variant of the same library
(read: every variants have the same common map), but some variants do not depend on libpthread.
So, I guess that in this situation it could make sense to wipe out the dependency over libpthread
for tachyon-nox. The idea behind this is that it might be possible to plug tachyon-nox to an
arbitrary variant.


Thanks,
Jerome

>