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Subject: Re: [OMPI users] MPI::Request::Test not working
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2012-01-04 07:21:38


It looks like you are using C++ improperly. I would suggest something like this (typed in email; not verified with a compiler):

MPI::Request Isend_request;
Isend_request = MPI::COMM_WORLD.Isend(...);

MPI::Status status;
if (Isend_request.Test(status)) {
    // ...
}

On Dec 30, 2011, at 10:21 PM, devendra rai wrote:

> Hello Everyone,
>
> I wrote a small C++ MPI program to do an ISend:
>
> /*some declarations here */
> MPI::Request Isend_request_status;
> ...
> ...
>
> /* do the transmission */
> Isend_request_status = MPI::COMM_WORLD.Isend(this->transmitbuffer, this->transmissionsize, MPI_BYTE, (this->dbIterator)->first, std::get<0>(this->TransmissionDetails));
>
> /* Check if the transmit was successful */
> if (MPI::Request::Test(Isend_request_status))
> {
> /* done :) */
> }
>
> However, building it gives the error:
>
> no matching function for call to ‘MPI::Request::Test(MPI::Request&)’
>
> I am using gcc-4.6 on Linux, with OpenMPI- 1.4.3.
>
> I looked up the headers for the calls:
>
> inline MPI::Request
> MPI::Comm::Isend(const void *buf, int count,
> const MPI::Datatype & datatype, int dest, int tag) const
>
> So, the MPI::COMM_WORLD::ISend(...) should return me variable of type MPI::Request.
>
> And,
>
> inline bool
> MPI::Request::Test(MPI::Status &status)
>
> This takes in the variable of type MPI::Status.
>
>
> So, two questions:
>
> (1). Is there a problem due to incompatible types? If so, how do I fix it?
> (2). Why would the MPI::Request::Test take in a different type than what is returned by MPI::COMM_WORLD::ISend(...)?
>
> It would really help if you could help me fix the example that I have shown.
>
> I understand it would be easier to do this in C, but there are project requirements that led me to C++.
>
> Can someone please help?
>
> Thanks a lot.
>
>
> Devendra
> sd
> _______________________________________________
> users mailing list
> users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/users

-- 
Jeff Squyres
jsquyres_at_[hidden]
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