* Jeff Squyres wrote on Wed, Feb 17, 2010 at 11:51:42PM CET: > On Feb 17, 2010, at 3:05 PM, Ralf Wildenhues wrote: > > > > The issue is that if the user has to specify -static to their linker, > > > they *also* have to specify --ompi:static, or Bad Things will happen. > > > Or, if they don't specify -static but *only* specify --ompi:static, > > > Bad Things will happen. In short: it seems like adding yet another > > > wrapper-compiler-specific flag to the MPI ecosystem will cause > > > confusion, fear, and possibly the death of some cats. > > > > Do you care for omitting -lopen-pal and -lorte only for capable Linux > > systems? With new-enough binutils, you should be able to use > > -Wl,--as-needed -Wl,--no-as-needed around these two libs. > > Mmmm. Good point. But I don't think it helps us on Solaris or OS X, does > it? (maybe it does on OS X?) Or do all linkers have some kind of option > like this? (this *might* be a way out, but I would probably need to be > convinced :-) )
No, I think only binutils ld (and gold) have this. Sorry. > > I'm not entirely sure I understand your argumentation for why libmpi > > from 1.5.x has to be binary incompatible, but I haven't fully thought > > through this yet. > > The context for this issue is so long that much was left out of my mail. > Here's this particular issue in a nutshell: > > - Open MPI v1.4.1 has libmpi at 0:1:0 and libopen-rte and libopen-pal both at > 0:0:0. > - Open MPI v1.4.1 links MPI apps against -lmpi -lopen-rte -lopen-pal. > - If we start .so versioning properly in v1.5, it's likely that libopen-rte > and libopen-pal will both be 1:0:0. > --> Note that these are both internal libraries; there are no symbols in > these libraries that are used in the MPI applications. > - Open MPI v1.5 libmpi *could* be 1:0:1. > - Hence, an a.out created for OMPI v1.4.1 would work fine with v1.5 libmpi. > - But that a.out would not work with v1.5 libopen-rte and libopen-pal. You could probably create fake empty libopen-rte and libopen-pal stub libraries with 0:0:0 purely for the sake of allowing such an a.out to still work (on systems with versioned sonames[1]). Since this doesn't actually use any of the APIs from those libraries, there is no problem here, and your 1.5 libmpi will pull in the 1:0:0 versions of the other two libraries. I understand if you decide not to go such ways, and in that case, I agree that bumping libmpi to 1:0:0 won't cause much extra pain. Cheers, Ralf [1] This includes many but probably not all systems with shared libraries. E.g., I think AIX without runtimelinking (-Wl,-brtl) would have a problem.
