[OT] Re: libxcb-xlib.la failures when building X11 with libxcb-1.2

[Eirik Byrkjeflot Anonsen]

Simon Thum <simon.thum at gmx.de> writes:

> Bill Crawford wrote:
>> included on the command line at link time. Libtool sort of abstracts this, but 
>> to do so it needs to keep track of what those dependencies are, and does so by 
>> storing them in this .la file.
> Thanks for the explanation. What baffles me is that AFAICT this
> introduces a lot of names to the linker, which you hadn't in mind when
> programming. So this practice is dangerous, because if you misspell
> something it may still be satisfied as libnever-heard-or-seen.so
> provides just your typo as a symbol, suppressing the proper error.

That's correct.  However, the likelihood of such misspellings are
fairly small as long as the shared objects use a reasonable naming
convention.  This is complicated by the traditional export-everything
policy of unix toolchains, though.

Although, in C/C++ such an error would also mean that the misspelling
matched some header file as well.  So when this happens I don't think
the link-time match is your main problem :)

On the other hand. I think it is a much bigger problem that two
libraries may in fact export the same name.  Now that really causes
problems, as you may get a completely different function than you
expected even though you spelled it correctly.

Or, when the (load-time) dependency tree of libraries ends up pulling
in mutually incompatible libraries (like when opera depended on on one
version of libpng, and libqt depended on a different version).

eirik