1 | .\"Copyright 2006-2008 Sun Microsystems, Inc. |
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2 | .\" Copyright (c) 1996 Thinking Machines Corporation |
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3 | .TH MPI_Type_get_true_extent 3 "Dec 08, 2009" "1.4" "Open MPI" |
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4 | .SH NAME |
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5 | \fBMPI_Type_get_true_extent\fP \- Returns the true lower bound and extent of a data type's corresponding typemap, ignoring MPI_UB and MPI_LB markers. |
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6 | |
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7 | .SH SYNTAX |
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8 | .ft R |
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9 | .SH C Syntax |
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10 | .nf |
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11 | #include <mpi.h> |
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12 | int MPI_Type_get_true_extent(MPI_Datatype \fIdatatype\fP, |
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13 | MPI_Aint *\fItrue_lb\fP, MPI_Aint *\fItrue_extent\fP) |
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14 | |
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15 | .SH Fortran Syntax (see FORTRAN 77 NOTES) |
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16 | .nf |
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17 | INCLUDE 'mpif.h' |
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18 | MPI_TYPE_GET_TRUE_EXTENT(\fIDATATYPE, TRUE_LB, TRUE_EXTENT, IERROR\fP) |
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19 | INTEGER \fIDATATYPE, IERROR\fP |
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20 | INTEGER(KIND=MPI_ADDRESS_KIND) \fITRUE_LB, TRUE_EXTENT\fP |
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21 | |
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22 | .SH C++ Syntax |
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23 | .nf |
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24 | #include <mpi.h> |
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25 | void MPI::Datatype::Get_true_extent(MPI::Aint& \fItrue_lb\fP, |
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26 | MPI::Aint& \fItrue_extent\fP) const |
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27 | |
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28 | .SH INPUT PARAMETER |
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29 | .ft R |
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30 | .TP 1i |
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31 | datatype |
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32 | Data type for which information is wanted (handle). |
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33 | .sp |
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34 | .SH OUTPUT PARAMETERS |
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35 | .ft R |
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36 | .TP 1i |
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37 | true_lb |
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38 | True lower bound of data type (integer). |
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39 | .TP 1i |
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40 | true_extent |
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41 | True size of data type (integer). |
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42 | .ft R |
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43 | .TP 1i |
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44 | IERROR |
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45 | Fortran only: Error status (integer). |
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46 | |
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47 | .SH DESCRIPTION |
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48 | .ft R |
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49 | The \fItrue_lb\fP parameter returns the offset of the lowest unit of store that is addressed by the data type, that is, the lower bound of the corresponding typemap, ignoring MPI_LB markers. The \fItrue_extent\fP parameter returns the true size of the data type, that is, the extent of the corresponding typemap, ignoring MPI_LB and MPI_UB markers, and performing no rounding for alignment. |
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50 | .sp |
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51 | The \fItrue_extent\fP is the minimum number of bytes of memory necessary to hold a data type, uncompressed. |
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52 | .sp |
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53 | See Section 4.14.3 of the MPI-2 standard for more detailed definitions of these parameters in relation to the typemap. |
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54 | |
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55 | .SH FORTRAN 77 NOTES |
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56 | .ft R |
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57 | The MPI standard prescribes portable Fortran syntax for |
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58 | the \fITRUE_LB\fP and \fITRUE_EXTENT\fP arguments only for Fortran 90. FORTRAN 77 |
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59 | users may use the non-portable syntax |
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60 | .sp |
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61 | .nf |
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62 | INTEGER*MPI_ADDRESS_KIND \fITRUE_LB\fP |
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63 | or |
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64 | INTEGER*MPI_ADDRESS_KIND \fITRUE_EXTENT\fP |
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65 | .fi |
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66 | .sp |
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67 | where MPI_ADDRESS_KIND is a constant defined in mpif.h |
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68 | and gives the length of the declared integer in bytes. |
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69 | |
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70 | .SH ERRORS |
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71 | Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ functions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism will be used to throw an MPI:Exception object. |
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72 | .sp |
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73 | Before the error value is returned, the current MPI error handler is |
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74 | called. By default, this error handler aborts the MPI job, except for I/O function errors. The error handler may be changed with MPI_Comm_set_errhandler; 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. |
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75 | |
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76 | |
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