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MPI_File_write_at_all_begin(3) man page (version 1.8.4)

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Name

MPI_File_write_at_all_begin - Writes a file at explicitly s pecified offsets; beginning part of a split collective routine (nonblocking).

Syntax


C Syntax
    #include <mpi.h>
    int MPI_File_write_at_all_begin(MPI_File fh, MPI_Offset
offset,
          const void *buf, int count, MPI_Datatype dat
atype)

Fortran Syntax (see FORTRAN 77 NOTES)


    INCLUDE ’mpif.h’
    MPI_FILE_WRITE_AT_ALL_BEGIN(FH, OFFSET, BUF,
 COUNT, DATATYPE, IERRO
R)
        <TYPE> BUF(*)
            INTEGER    FH, COUNT, DATATYPE, IERROR
        INTEGER(KIND=MPI_OFFSET_KIND) OFFSET

C++ Syntax


#include <mpi.h>
void MPI::File::Write_at_all_begin(MPI::Offset offset,
    const void* buf, int count,
    const MPI::Datatype& datatype)

Input/Output Parameter

fh
File handle (handle).

Input Parameters

offset
File offset (handle).
buf
Initial address of buffer (choice).
count
Number of elements in buffer (integer).
datatype
Data type of each buffer element (handle).

Output Parameter

IERROR
Fortran only: Error status (integer).

Description

MPI_File_write_at_all_begin is the beginning part of a split colle ctive, that is, a nonblocking routine that a ttempts to write into the file associa ted with fh (at the offset position) a total number of count data items having datatype type from the user’s buffer buf. The offset is in etype units relative to the current view. That is , holes are not counted when locating an offset. The data is written into those parts of t he file specified by the current view.

Fortran 77 Notes

The MPI standard prescribes portable Fortran syntax for the OFFSET argument only for Fortran 90. FORTRAN 77 users may use the non-portable syntax


     INTEGER*MPI_OFFSET_KIND OFFSET

where MPI_OFFSET_KIND is a constant defined in mpif.h and gives the length of the declared integer in bytes.

Notes

All the nonblocking collective routines for data access are "split " into two routines, each with _begin or _en d as a suffix. These split collective routines are subject to the semantic rules described i n Section 9.4.5 of the MPI-2 standard.

Errors

Almost all MPI routines return an error value; C routines as the v alue of the function and Fortran routi nes in the last argument. C++ functions do n ot return errors. If the default error handler is set to MPI::ERRORS_THROW_E XCEPTIONS, then on error the C ++ exception m echanism will be used to throw an MPI::Exception object.

Before the error value is returned, the current MPI error handler is called. For MPI I/O function errors, the default error handler is set to MPI_ERRORS_RETURN. The error ha ndler may be changed with MPI_File_set_errha ndler; the predefined error handler MPI_ERRORS_ARE_FAT AL may be used to make I/O errors fatal. Note that M PI does not gu arantee that a n MPI program can continue past an error.


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