MPI_Sendrecv

Synopsis

int MPI_Sendrecv(const void *sendbuf, int sendcount, MPI_Datatype sendtype,
                 int dest, int sendtag, void *recvbuf, int recvcount,
                 MPI_Datatype recvtype, int source, int recvtag, MPI_Comm comm,
                 MPI_Status *status)

int MPI_Sendrecv_c(const void *sendbuf, MPI_Count sendcount,
                   MPI_Datatype sendtype, int dest, int sendtag, void *recvbuf,
                   MPI_Count recvcount, MPI_Datatype recvtype, int source,
                   int recvtag, MPI_Comm comm, MPI_Status *status)

Input Parameters

sendbuf

initial address of send buffer (choice)

sendcount

number of elements in send buffer (non-negative integer)

sendtype

type of elements in send buffer (handle)

dest

rank of destination (integer)

sendtag

send tag (integer)

recvcount

number of elements in receive buffer (non-negative integer)

recvtype

type of elements receive buffer element (handle)

source

rank of source or MPI_ANY_SOURCE (integer)

recvtag

receive tag or MPI_ANY_TAG (integer)

comm

communicator (handle)

Output Parameters

recvbuf

initial address of receive buffer (choice)

status

status object (Status)

Thread and Interrupt Safety

This routine is thread-safe. This means that this routine may be safely used by multiple threads without the need for any user-provided thread locks. However, the routine is not interrupt safe. Typically, this is due to the use of memory allocation routines such as malloc or other non-MPICH runtime routines that are themselves not interrupt-safe.

Notes for Fortran

All MPI objects (e.g., MPI_Datatype, MPI_Comm) are of type INTEGER in Fortran.

Errors

All MPI routines (except MPI_Wtime and MPI_Wtick) return an error value; C routines as the value of the function and Fortran routines in the last argument. Before the value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job. The error handler may be changed with MPI_Comm_set_errhandler (for communicators), MPI_File_set_errhandler (for files), and MPI_Win_set_errhandler (for RMA windows). The MPI-1 routine MPI_Errhandler_set may be used but its use is deprecated. The predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error; however, MPI implementations will attempt to continue whenever possible.

MPI_SUCCESS

No error; MPI routine completed successfully.

MPI_ERR_ARG

Invalid argument. Some argument is invalid and is not identified by a specific error class (e.g., MPI_ERR_RANK).

MPI_ERR_BUFFER

Invalid buffer pointer. Usually a null buffer where one is not valid.

MPI_ERR_COMM

Invalid communicator. A common error is to use a null communicator in a call (not even allowed in MPI_Comm_rank).

MPI_ERR_COUNT

Invalid count argument. Count arguments must be non-negative; a count of zero is often valid.

MPI_ERR_RANK

Invalid source or destination rank. Ranks must be between zero and the size of the communicator minus one; ranks in a receive (MPI_Recv, MPI_Irecv, MPI_Sendrecv, etc.) may also be MPI_ANY_SOURCE.

MPI_ERR_TAG

Invalid tag argument. Tags must be non-negative; tags in a receive (MPI_Recv, MPI_Irecv, MPI_Sendrecv, etc.) may also be MPI_ANY_TAG. The largest tag value is available through the the attribute MPI_TAG_UB.

MPI_ERR_TYPE

Invalid datatype argument. Additionally, this error can occur if an uncommitted MPI_Datatype (see MPI_Type_commit) is used in a communication call.

MPI_ERR_OTHER

Other error; use MPI_Error_string to get more information about this error code.