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Subject: Re: [OMPI users] Windows C++ Linker Error "unresolved symbol" for MPI::Datatype::Free
From: Damien Hocking (damien_at_[hidden])
Date: 2013-02-21 10:59:41


Well this is interesting. The linker can't find that because
MPI::Datatype::Free isn't implemented on the Windows build (in
datatype_inln.h). It's declared in datatype.h though. It's not there
in the Linux version either, so I don't know where the Linux build is
getting that symbol from, that link should fail too. Is the C++ version
of OpenMPI actually broken overall?

The Windows support is another issue. I think it's semi-officially
deprecated.

Damien

On 20/02/2013 11:20 PM, Hartman, Todd W. wrote:
> I'm trying to build a simple Open MPI application for Windows. I've installed the binaries for OpenMPI-v1.6.2 (64-bit). I've also installed Visual Studio 2010. The machine(s) are Windows 7 x64.
>
>
> When I attempt to compile a simple program that uses MPI::Send(), I get a linker error saying that it cannot resolve MPI::Datatype::Free().
>
> Here's a minimal example:
>
> ---------------------------------------------------
> #include <mpi.h>
> #include <iostream>
> int main( int argc, char** argv ) {
> MPI::Init(argc,argv);
>
> // Meant to run with 2 processes.
> if (MPI::COMM_WORLD.Get_rank() == 0) {
> int data;
> MPI::COMM_WORLD.Recv(&data,1,MPI_INT,1,0);
> std::cout << "received " << data << std::endl;
> } else {
> int data = 0xdead;
> std::cout << "sending " << data << std::endl;
> MPI::COMM_WORLD.Send(&data,1,MPI_INT,0,0);
> }
>
> MPI::Finalize();
> }
> ---------------------------------------------------
>
> When I compile it:
>
> mpic++ send_compile.cpp -o send_compile.exe -DOMPI_IMPORTS -DOPAL_IMPORTS -DORTE_IMPORTS
>
>
> ---------------------------------------------------
> Microsoft (R) C/C++ Optimizing Compiler Version 16.00.40219.01 for x64
> Copyright (C) Microsoft Corporation. All rights reserved.
>
>
>
>
> cl : Command line warning D9035 : option 'o' has been deprecated and will be removed in a future release
> send_compile.cpp
> Microsoft (R) Incremental Linker Version 10.00.40219.01
> Copyright (C) Microsoft Corporation. All rights reserved.
>
> /out:send_compile.exe
> /out:send_compile.exe
> "/LIBPATH:C:\Program Files (x86)\OpenMPI_v1.6.2-x64/lib"
> libmpi_cxx.lib
> libmpi.lib
> libopen-pal.lib
> libopen-rte.lib
> advapi32.lib
> Ws2_32.lib
> shlwapi.lib
> send_compile.obj
> send_compile.obj : error LNK2001: unresolved external symbol "public: virtual void __cdecl MPI::Datatype::Free(void)" (?Free_at_Datatype@MPI@@UEAAXXZ)
> send_compile.exe : fatal error LNK1120: 1 unresolved externals
> ---------------------------------------------------
>
> This program compiles and runs without complaint on an Ubuntu machine around here. I don't know what the problem is. Open MPI's documentation didn't say anything about adding the CPP defines (OMPI_IMPORTS, OPAL_IMPORTS, ORTE_IMPORTS) whose absence were causing other linker errors similar to this. Google found some items in the mailing list archive. I cannot find any information about this particular problem, though.
>
> I tried using dumpbin to get symbols that were in the .lib files installed by MPI, but didn't find any reference to that function name. I didn't find any answers looking in the MPI headers, either.
>
> I have a similar program in C that compiles and runs fine on this Windows machine. I don't know what I'm doing wrong with C++. Can someone point me in the right direction? Is there some documentation regarding getting things to work on Windows? The release notes don't address this problem, and I can't find any other documentation related to what might be different from *nix to Windows (WRT to Open MPI).
>
> Thanks.
>
>
> todd.
>
> P.S. This is copied from a StackOverflow question I posted (http://stackoverflow.com/questions/14988099/open-mpi-c-link-error-mpidatatypefree-on-windows). Forgive the cross-posting.
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