1MPI_Buffer_attach(3) LAM/MPI MPI_Buffer_attach(3)
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6 MPI_Buffer_attach - Attaches a user-defined buffer for sending
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9 #include <mpi.h>
10 int MPI_Buffer_attach(void *buf, int size)
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13 buf - initial buffer address (choice)
14 size - buffer size, in bytes (integer)
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18 The size given should be the sum of the sizes of all outstanding Bsends
19 that you intend to have, plus a few hundred bytes for each Bsend that
20 you do. For the purposes of calculating size, you should use
21 MPI_Pack_size . In other words, in the code
22 MPI_Buffer_attach( buffer, size );
24 MPI_Bsend( ..., count=20, datatype=type1, ... );
25 .
26 .
27 .
28 MPI_Bsend( ..., count=40, datatype=type2, ... );
29 the value of size in the MPI_Buffer_attach call should be greater than
32 the value computed by
33 MPI_Pack_size(20, type1, comm, &s1);
35 MPI_Pack_size(40, type2, comm, &s2);
36 size = s1 + s2 + 2 * MPI_BSEND_OVERHEAD;
37 MPI_Bsend_overhead gives the maximum amount of space that may be used
40 in the buffer for use by the Bsend routines in using the buffer. This
41 value is in mpi.h (for C) and mpif.h (for Fortran).
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45 All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have
46 an additional argument ierr at the end of the argument list. ierr is
47 an integer and has the same meaning as the return value of the routine
48 in C. In Fortran, MPI routines are subroutines, and are invoked with
49 the call statement.
50 All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
52 Fortran.
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56 If an error occurs in an MPI function, the current MPI error handler is
57 called to handle it. By default, this error handler aborts the MPI
58 job. The error handler may be changed with MPI_Errhandler_set ; the
59 predefined error handler MPI_ERRORS_RETURN may be used to cause error
60 values to be returned (in C and Fortran; this error handler is less
61 useful in with the C++ MPI bindings. The predefined error handler
62 MPI::ERRORS_THROW_EXCEPTIONS should be used in C++ if the error value
63 needs to be recovered). Note that MPI does not guarantee that an MPI
64 program can continue past an error.
65 All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error
67 value; C routines as the value of the function and Fortran routines in
68 the last argument. The C++ bindings for MPI do not return error val‐
69 ues; instead, error values are communicated by throwing exceptions of
70 type MPI::Exception (but not by default). Exceptions are only thrown
71 if the error value is not MPI::SUCCESS .
72 Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI
75 functions will return upon an error, there will be no way to recover
76 what the actual error value was.
77 MPI_SUCCESS
78 - No error; MPI routine completed successfully.
79 MPI_ERR_BUFFER
80 - Invalid buffer pointer. Usually a null buffer where one is
81 not valid.
82 MPI_ERR_INTERN
83 - An internal error has been detected. This is fatal. Please
84 send a bug report to the LAM mailing list (see http://www.lam-
85 mpi.org/contact.php ).
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89 MPI_Buffer_detach, MPI_Bsend
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93 For more information, please see the official MPI Forum web site, which
94 contains the text of both the MPI-1 and MPI-2 standards. These docu‐
95 ments contain detailed information about each MPI function (most of
96 which is not duplicated in these man pages).
97 http://www.mpi-forum.org/
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103 The LAM Team would like the thank the MPICH Team for the handy program
104 to generate man pages ("doctext" from ftp://ftp.mcs.anl.gov/pub/sow‐
105 ing/sowing.tar.gz ), the initial formatting, and some initial text for
106 most of the MPI-1 man pages.
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109 bufattach.c
110LAM/MPI 7.1.2 2/23/2006 MPI_Buffer_attach(3)