1MPIL_Type_id(3) LAM/MPI MPIL_Type_id(3)
2
6 MPIL_Type_id - LAM/MPI-specific function to return the type ID of an
7 MPI datatype
8
10 #include <mpi.h>
11 int MPIL_Type_id(MPI_Datatype dtype, int *ptid)
12
14 dtype - MPI datatype (handle)
15
18 ptid - datatype ID (integer)
19
22 In the LAM implementation of MPI, each communicator has an integer con‐
23 text ID associated with it for synchronizing on different contexts.
24 This ID is global to all the processes in the communicator's group, and
25 uniquely identifies that communicator for each process. These proper‐
26 ties allow the processes to safely exchange messages without interfer‐
27 ence from operations on other communicators.
28 The MPI standard does not provide a way to access/view this implementa‐
30 tion-dependent synchronization since communicators are opaque objects.
31 Users do not need such access for normal MPI operations. On the other
32 hand, when debugging MPI applications, the opaque nature of communica‐
33 tors hinders the user's efforts. This is especially true on fully
34 observable systems such as LAM, where users can monitor the full state
35 of the processes and message queues, which includes the context ID (see
36 mpitask (1) and mpimsg (1)).
37 This is a LAM/MPI-specific function and is intended mainly for debug‐
39 ging. If this function is used, it should be used in conjunction with
40 the LAM_MPI C preprocessor macro
41 #if LAM_MPI
43 int tid
44 MPIL_Type_id(MPI_INT, &tid);
45 #endif
46
50 All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have
51 an additional argument ierr at the end of the argument list. ierr is
52 an integer and has the same meaning as the return value of the routine
53 in C. In Fortran, MPI routines are subroutines, and are invoked with
54 the call statement.
55 All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
57 Fortran.
58
61 If an error occurs in an MPI function, the current MPI error handler is
62 called to handle it. By default, this error handler aborts the MPI
63 job. The error handler may be changed with MPI_Errhandler_set ; the
64 predefined error handler MPI_ERRORS_RETURN may be used to cause error
65 values to be returned (in C and Fortran; this error handler is less
66 useful in with the C++ MPI bindings. The predefined error handler
67 MPI::ERRORS_THROW_EXCEPTIONS should be used in C++ if the error value
68 needs to be recovered). Note that MPI does not guarantee that an MPI
69 program can continue past an error.
70 All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error
72 value; C routines as the value of the function and Fortran routines in
73 the last argument. The C++ bindings for MPI do not return error val‐
74 ues; instead, error values are communicated by throwing exceptions of
75 type MPI::Exception (but not by default). Exceptions are only thrown
76 if the error value is not MPI::SUCCESS .
77 Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI
80 functions will return upon an error, there will be no way to recover
81 what the actual error value was.
82 MPI_SUCCESS
83 - No error; MPI routine completed successfully.
84 MPI_ERR_TYPE
85 - Invalid datatype argument. May be an uncommitted MPI_Datatype
86 (see MPI_Type_commit ).
87 MPI_ERR_ARG
88 - Invalid argument. Some argument is invalid and is not identi‐
89 fied by a specific error class. This is typically a NULL
90 pointer or other such error.
91
94 MPIL_Comm_gps, MPIL_Comm_id
95
97 mpil_id.c
98LAM/MPI 7.1.2 2/23/2006 MPIL_Type_id(3)