dynamic library help

[Clint Whaley-2]

Guys,

I've been trying to improve ATLAS's dynamic library support for 3.9.4.  On
linux, I build .so using ld, and the default is that it is OK to have
missing symbols, so everything works OK.  On Windows & OS X, however,
it is not OK to have missing symbols.  Therefore, when I build
liblapack.dylib (OSX, would be liblapack.dll under windows), I have to
specify all the things it depends on.  So, for instance, I wind up with
something like (here I give the OS X command, but the dependency problem
is the same for using ld under Windows):

   libtool -dynamic -o ../liblapack.dylib <flags> *.o \
            ../libf77blas.dylib ../libf77blas.dylib ../libcblas.dylib

The problem is that liblapack.dylib doesn't *always* depend on libcblas:
if the user specifies it should depend on libptcblas.dylib instead.
My fear is that even if the user specifies:
   -llapack -lptf77blas -lptcblas
he might get the serial interface, if I create the shared object as using
the serial libraries.

I can figure this out by doing timings, of course, but I wonder if anyone
knows for sure what happens in this case?  Is there anyway to say that
symbols can be supplied by a choice of libraries, rather than just one?

The safe thing to do is to create a ptlapack that has dependence on the
ptblas, with lapack being dependent on the serial blas.  This has two
drawbacks: (1) We duplicate lapack, a very large library, in memory
(2) the dynamic link no longer works like the static . . .

Any info appreciated,
Clint

**************************************************************************
** R. Clint Whaley, PhD ** Assist Prof, UTSA ** www.cs.utsa.edu/~whaley **
**************************************************************************

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[Agile Aspect]

I had a similar issue under Linux, and if I recall correctly,  I ended up
having to link in the FORTRAN libraries too in order to resolve all the
symbols. (I think for gcc 3.x this was libg2c.)

Also,  one needs to ensure all the shared libraries have been compiled
PIC flag (position independent code.)

Clint Whaley wrote:

> Guys,
>
> I've been trying to improve ATLAS's dynamic library support for 3.9.4.  On
> linux, I build .so using ld, and the default is that it is OK to have
> missing symbols, so everything works OK.  On Windows & OS X, however,
> it is not OK to have missing symbols.  Therefore, when I build
> liblapack.dylib (OSX, would be liblapack.dll under windows), I have to
> specify all the things it depends on.  So, for instance, I wind up with
> something like (here I give the OS X command, but the dependency problem
> is the same for using ld under Windows):
>
>    libtool -dynamic -o ../liblapack.dylib <flags> *.o \
>             ../libf77blas.dylib ../libf77blas.dylib ../libcblas.dylib
>
> The problem is that liblapack.dylib doesn't *always* depend on libcblas:
> if the user specifies it should depend on libptcblas.dylib instead.
> My fear is that even if the user specifies:
>    -llapack -lptf77blas -lptcblas
> he might get the serial interface, if I create the shared object as using
> the serial libraries.
>
> I can figure this out by doing timings, of course, but I wonder if anyone
> knows for sure what happens in this case?  Is there anyway to say that
> symbols can be supplied by a choice of libraries, rather than just one?
>
> The safe thing to do is to create a ptlapack that has dependence on the
> ptblas, with lapack being dependent on the serial blas.  This has two
> drawbacks: (1) We duplicate lapack, a very large library, in memory
> (2) the dynamic link no longer works like the static . . .
>
> Any info appreciated,
> Clint
>
> **************************************************************************
> ** R. Clint Whaley, PhD ** Assist Prof, UTSA ** www.cs.utsa.edu/~whaley **
> **************************************************************************
>
> -------------------------------------------------------------------------
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> _______________________________________________
> Math-atlas-devel mailing list
> Math-atlas-devel@...
> https://lists.sourceforge.net/lists/listinfo/math-atlas-devel
>
>  

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