1MPI_Ibsend(3) LAM/MPI MPI_Ibsend(3)
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6 MPI_Ibsend - Starts a nonblocking buffered send
7
9 #include <mpi.h>
10 int MPI_Ibsend(void *buf, int count, MPI_Datatype dtype,
11 int dest, int tag, MPI_Comm comm,
12 MPI_Request *preq)
13
15 buf - initial address of send buffer (choice)
16 count - number of elements in send buffer (integer)
17 dtype - datatype of each send buffer element (handle)
18 dest - rank of destination (integer)
19 tag - message tag (integer)
20 comm - communicator (handle)
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24 preq - communication request (handle)
25
28 It is generally a bad idea to use the MPI_Ibsend function, as it guar‐
29 antees that the entire message will suffer the overhead of an addi‐
30 tional memory copy. For large messages, or when shared memory message
31 transports are being used, this overhead can be quite expensive.
32 The communication started with this function is not guaranteed to
34 progress or complete until req has been given to one of the test or
35 wait functions ( MPI_Test , MPI_Testall , MPI_Testany , MPI_Testsome ,
36 MPI_Wait , MPI_Waitall , MPI_Waitany , MPI_Waitsome ).
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40 All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have
41 an additional argument ierr at the end of the argument list. ierr is
42 an integer and has the same meaning as the return value of the routine
43 in C. In Fortran, MPI routines are subroutines, and are invoked with
44 the call statement.
45 All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
47 Fortran.
48
51 If an error occurs in an MPI function, the current MPI error handler is
52 called to handle it. By default, this error handler aborts the MPI
53 job. The error handler may be changed with MPI_Errhandler_set ; the
54 predefined error handler MPI_ERRORS_RETURN may be used to cause error
55 values to be returned (in C and Fortran; this error handler is less
56 useful in with the C++ MPI bindings. The predefined error handler
57 MPI::ERRORS_THROW_EXCEPTIONS should be used in C++ if the error value
58 needs to be recovered). Note that MPI does not guarantee that an MPI
59 program can continue past an error.
60 All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error
62 value; C routines as the value of the function and Fortran routines in
63 the last argument. The C++ bindings for MPI do not return error val‐
64 ues; instead, error values are communicated by throwing exceptions of
65 type MPI::Exception (but not by default). Exceptions are only thrown
66 if the error value is not MPI::SUCCESS .
67 Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI
70 functions will return upon an error, there will be no way to recover
71 what the actual error value was.
72 MPI_SUCCESS
73 - No error; MPI routine completed successfully.
74 MPI_ERR_COMM
75 - Invalid communicator. A common error is to use a null commu‐
76 nicator in a call (not even allowed in MPI_Comm_rank ).
77 MPI_ERR_COUNT
78 - Invalid count argument. Count arguments must be non-negative;
79 a count of zero is often valid.
80 MPI_ERR_TYPE
81 - Invalid datatype argument. May be an uncommitted MPI_Datatype
82 (see MPI_Type_commit ).
83 MPI_ERR_TAG
84 - Invalid tag argument. Tags must be non-negative; tags in a
85 receive ( MPI_Recv , MPI_Irecv , MPI_Sendrecv , etc.) may also
86 be MPI_ANY_TAG . The largest tag value is available through the
87 the attribute MPI_TAG_UB .
88 MPI_ERR_RANK
90 - Invalid source or destination rank. Ranks must be between
91 zero and the size of the communicator minus one; ranks in a
92 receive ( MPI_Recv , MPI_Irecv , MPI_Sendrecv , etc.) may also
93 be MPI_ANY_SOURCE .
94 MPI_ERR_BUFFER
96 - Invalid buffer pointer. Usually a null buffer where one is
97 not valid.
98
101 MPI_Bsend, MPI_Test, MPI_Testall, MPI_Testany, MPI_Testsome, MPI_Wait,
102 MPI_Waitall, MPI_Waitany, MPI_Waitsome
103
106 For more information, please see the official MPI Forum web site, which
107 contains the text of both the MPI-1 and MPI-2 standards. These docu‐
108 ments contain detailed information about each MPI function (most of
109 which is not duplicated in these man pages).
110 http://www.mpi-forum.org/
112
116 The LAM Team would like the thank the MPICH Team for the handy program
117 to generate man pages ("doctext" from ftp://ftp.mcs.anl.gov/pub/sow‐
118 ing/sowing.tar.gz ), the initial formatting, and some initial text for
119 most of the MPI-1 man pages.
120
122 ibsend.c
123LAM/MPI 7.1.2 2/23/2006 MPI_Ibsend(3)