On 25 May 2013 00:25, Michael Tokarev <m...@tls.msk.ru> wrote: > 25.05.2013 00:07, Ed Maste wrote: >> When probing for ncurses, try pkg-config first rather than after >> explicit -lncurses and -lcurses. This fixes static linking in the case >> that ncurses has additional dependencies, such as -ltinfo (as on FreeBSD). > > This is not a FreeBSD-specific thing, this is the way how current > ncurses works -- they separated a bunch of functions into a new > library, libtinfo.
Right, I don't mean to apply it was FreeBSD-specific. Presumably QEMU builds with --static on at least some Linux distros, so I assumed they must not have the external libtinfo dep for static linking (because they build libncurses.a with it built-in, say). > But this is interesting. > > I'm not sure I agree with this approach. When we're building using > shared library, libncurses.so already links with libtinfo.so, so we > don't need to link executable itself with libtinfo.so, since executable > itself uses none of its functions. Right, and pkg-config doesn't include -ltinfo when using dynamic linking. > On the other hand, the current logic appears to be fine, -- we first > link with just -lncurses, and if that fails, we also try pkg-config --libs -- > because, maybe, we're linking statically and in that case, additional > libs from pkg-config may help. Except that the test snippet in configure will successfully link statically without -ltinfo, so configure doesn't make it to the pkg-config test. > From yet another point of view, we may use --as-needed linker flag > and just ignore all the above. > > Here, it is interesting to note that pkg-config does not actually do > the right thing in this case. Because practically, it should have > one extra flag, something like --static-libs (or --libs --static), > and it should actually be different from plain --libs. In fact, it does: feynman% pkg-config --libs ncurses -L/usr/local/lib -lncurses feynman% pkg-config --static --libs ncurses -L/usr/local/lib -lncurses -ltinfo and the configure script adds --static to QEMU_PKG_CONFIG_FLAGS when necessary.
