1MPI_Request_free(3) LAM/MPI MPI_Request_free(3)
2
6 MPI_Request_free - Frees a communication request object
7
9 #include <mpi.h>
10 int MPI_Request_free(MPI_Request *preq)
11
13 preq - communication request (handle)
14
17 This routine is normally used to free persistent requests created with
18 either MPI_Recv_init or MPI_Send_init (and friends). However, it can
19 be used to free a request created with MPI_Irecv or MPI_Isend (and
20 friends); in that case the user can not use the test/wait routines on
21 the request.
22 It is permitted to free an active request. However, once freed, you
24 can not use the request in a wait or test routine (e.g., MPI_Wait ).
25 preq is set to MPI_REQUEST_NULL upon completion.
27
30 All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have
31 an additional argument ierr at the end of the argument list. ierr is
32 an integer and has the same meaning as the return value of the routine
33 in C. In Fortran, MPI routines are subroutines, and are invoked with
34 the call statement.
35 All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
37 Fortran.
38
41 If an error occurs in an MPI function, the current MPI error handler is
42 called to handle it. By default, this error handler aborts the MPI
43 job. The error handler may be changed with MPI_Errhandler_set ; the
44 predefined error handler MPI_ERRORS_RETURN may be used to cause error
45 values to be returned (in C and Fortran; this error handler is less
46 useful in with the C++ MPI bindings. The predefined error handler
47 MPI::ERRORS_THROW_EXCEPTIONS should be used in C++ if the error value
48 needs to be recovered). Note that MPI does not guarantee that an MPI
49 program can continue past an error.
50 All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error
52 value; C routines as the value of the function and Fortran routines in
53 the last argument. The C++ bindings for MPI do not return error val‐
54 ues; instead, error values are communicated by throwing exceptions of
55 type MPI::Exception (but not by default). Exceptions are only thrown
56 if the error value is not MPI::SUCCESS .
57 Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI
60 functions will return upon an error, there will be no way to recover
61 what the actual error value was.
62 MPI_SUCCESS
63 - No error; MPI routine completed successfully.
64 MPI_ERR_REQUEST
65 - Invalid MPI_Request ; either null or, MPI_REQUEST_NULL , in
66 the case of a MPI_Start or MPI_Startall , not a persistent
67 request.
68 MPI_ERR_ARG
69 - Invalid argument. Some argument is invalid and is not identi‐
70 fied by a specific error class. This is typically a NULL
71 pointer or other such error.
72
75 also: MPI_Isend, MPI_Irecv, MPI_Issend, MPI_Ibsend, MPI_Irsend,
76 MPI_Recv_init, MPI_Send_init, MPI_Ssend_init, MPI_Rsend_init, MPI_Wait,
77 MPI_Test, MPI_Waitall, MPI_Waitany, MPI_Waitsome, MPI_Testall, MPI_Tes‐
78 tany, MPI_Testsome
79
82 For more information, please see the official MPI Forum web site, which
83 contains the text of both the MPI-1 and MPI-2 standards. These docu‐
84 ments contain detailed information about each MPI function (most of
85 which is not duplicated in these man pages).
86 http://www.mpi-forum.org/
88
92 The LAM Team would like the thank the MPICH Team for the handy program
93 to generate man pages ("doctext" from ftp://ftp.mcs.anl.gov/pub/sow‐
94 ing/sowing.tar.gz ), the initial formatting, and some initial text for
95 most of the MPI-1 man pages.
96
98 reqfree.c
99LAM/MPI 7.1.2 2/23/2006 MPI_Request_free(3)