Ralph and Jeff:
Thanks for your replies to my questions about compiling a 32-bit MPI library
for Forth.
Ralph wrote:
IIRC, you would need to write a wrapper to let Forth access C-based functions, yes? You could
configure and build OMPI as a 32-bit library, and libmpi.so is C, so that isn?t an issue.
I'm using Microprocessor Engineering Ltd.'s Forth, which can import any executable image saved in a
.so formatted file. In Forth, two commands make the link to the executable. The command:
LIBRARY <filename>
opens the library file. Then the command:
EXTERN: <return value> name ( < list of passed parameters> )
makes the function callable from within Forth. (The parameters and return values are passed on the
stack.) So, once you've got a usable library available, the process is trivial.
What compiler are you planning to use (as the cmd line options may vary a bit)?
I only have my machine here in the lab to work with, and I don't have a lot of information on it.
Entering "mpicc --version" I get:
gcc (Debian 4.9.2-10) 4.9.2
Ralph's suggestion is exactly what I've tried so far. I've written a small C file where I include
MPI.h and then write functions that are just wrappers for the MPI functions, such as:
int FMPI_Finalize()
{
return MPI_Finalize():
}
Then I try to compile the library file in 32-bit mode. The first command is:
mpicc -fPIC -m32 -c libtest.c
Then the second is:
mpicc -shared -m32 -o libmpi.so libtest.o
As you can see below, compiling the object file works. But the second command, linking libtest.o
and writing the shared library, fails. Can you see what's wrong?
rwagner@tuxcfd10:~/engrhome/CSU/LibTests$ mpicc -fPIC -m32 -c libtest.c
rwagner@tuxcfd10:~/engrhome/CSU/LibTests$ mpicc -shared -m32 -o libmpi.so
libtest.o
/usr/bin/ld: skipping incompatible /usr//lib/libmpi.so when searching for -lmpi
/usr/bin/ld: skipping incompatible /usr/lib/openmpi/lib/libmpi.so when
searching for -lmpi
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.9/../../../libmpi.so when
searching for -lmpi
/usr/bin/ld: skipping incompatible //usr/lib/libmpi.so when searching for -lmpi
/usr/bin/ld: cannot find -lmpi
/usr/bin/ld: cannot find -lhwloc
collect2: error: ld returned 1 exit status
And for added info, these two commands succeed when I don't use the -m32 switch. The library comes
out as you'd expect it to, but as a 64-bit version.
Regards,
Rich Wagner
Aerospace Engineer
Grad Student
Montrose, CO, Fort Collins, CO and points elsewhere...
