Em Mon, 26 Sep 2016 18:46:40 +0300 Sakari Ailus <sakari.ailus@xxxxxx> escreveu: > Hi Mauro, > > On Mon, Sep 19, 2016 at 11:19:12AM -0300, Mauro Carvalho Chehab wrote: > > Em Mon, 19 Sep 2016 16:21:30 +0300 > > Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> escreveu: > > > > > Hi Mauro, > > > > > > On 09/19/16 14:22, Mauro Carvalho Chehab wrote: > > > > Em Mon, 19 Sep 2016 13:50:25 +0300 > > > > Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> escreveu: > > > > > > > >> v4l2-compliance and v4l2-ctl depend on librt and libpthread. The symbols > > > >> are found by the linker only if these libraries are specified after the > > > >> objects that depend on them. > > > >> > > > >> As LDFLAGS variable end up expanded on libtool command line before LDADD, > > > >> move the libraries to LDADD after local objects. -lpthread is added as on > > > >> some systems librt depends on libpthread. This is the case on Ubuntu 16.04 > > > >> for instance. > > > >> > > > >> After this patch, creating a static build using the command > > > >> > > > >> LDFLAGS="--static -static" ./configure --disable-shared --enable-static > > > > > > > > It sounds weird to use LDFLAGS="--static -static" here, as the > > > > configure options are already asking for static. > > > > > > > > IMHO, the right way would be to change configure.ac to add those LDFLAGS > > > > when --disable-shared is used. > > > > > > That's one option, but then shared libraries won't be built at all. > > > > Well, my understanding is that --disable-shared is meant to disable > > building the shared library build :) > > > > > I'm > > > not sure what would be the use cases for that, though: static linking > > > isn't very commonly needed except when you need to run the binaries > > > elsewhere (for whatever reason) where you don't have the libraries you > > > linked against available. > > > > Yeah, that's the common usage. It is also interesting if someone > > wants to build 2 versions of the same utility, each using a > > different library, for testing purposes. > > > > The usecase I can't see is to use --disable-shared but keeping > > using the dynamic library for the exec files. > > There are three primary options here, > > 1. build an entirely static binary, > 2. build a binary that relies on dynamic libraries as well and > 3. build a binary that relies on dynamic libraries outside v4l-utils package > but that links v4l-utils originating libraries statically. > > If you say 3. is not needed then we could just use --disable-shared also to > tell that static binaries are to be built. > > 3. is always used for libv4l2subdev and libmediactl as the libraries do not > have stable APIs. Sakari, I can't see what you mean by scenario (2). I mean, if --disable-shared is called, it *should not* use dynamic libraries for any library provided by v4l-utils, as the generated binaries will either: a) don't work, because those libraries weren't built; b) will do the wrong thing, as they'll be dynamically linked to an older version of the library. So, there are only 3 possible scenarios, IMHO: 1) dynamic libraries, dynamic execs 2) static v4l-utils libraries, static execs 3) static v4l-utils libraries, static links for v4l-utils libs, dyn for the rest. In practice, I don't see any reason for keeping support for both (2) and (3), as all usecases for (3) can be covered by a fully static exec. It is also very confusing for one to understand that. For example, right now, we have those static/shared options: --enable-static[=PKGS] build static libraries [default=yes] --enable-shared[=PKGS] build shared libraries [default=yes] with, IMHO, sounds confusing, as those options don't seem to be orthogonal. I mean, what happens someone calls ./configure with: ./configure --disable-static --disable-shared Thanks, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
