mpi_file_read_at_all_begin(3openmpi) [osx man page]
MPI_File_read_at_all_begin(3OpenMPI) MPI_File_read_at_all_begin(3OpenMPI) NAME
MPI_File_read_at_all_begin - Reads a file at explicitly specified offsets; beginning part of a split collective routine (nonblocking). SYNTAX
C Syntax #include <mpi.h> int MPI_File_read_at_all_begin(MPI_File fh, MPI_Offset offset, void *buf, int count, MPI_Datatype datatype) Fortran Syntax (see FORTRAN 77 NOTES) INCLUDE 'mpif.h' MPI_FILE_READ_AT_ALL_BEGIN(FH, OFFSET, BUF, COUNT, DATATYPE, IERROR) <type> BUF(*) INTEGER FH, COUNT, DATATYPE, IERROR INTEGER(KIND=MPI_OFFSET_KIND) OFFSET C++ Syntax #include <mpi.h> void MPI::File::Read_at_all_begin(MPI::Offset offset, void* buf, int count, const MPI::Datatype& datatype) INPUT PARAMETERS
fh File handle (handle). offset File offset (integer). count Number of elements in buffer (integer). datatype Data type of each buffer element. OUTPUT PARAMETERS
buf Initial address of buffer (choice). IERROR Fortran only: Error status (integer). DESCRIPTION
MPI_File_read_at_all_begin is the beginning part of a split collective routine that attempts to read from the file associated with fh (at the offset position) a total number of count data items having datatype type into the user's buffer buf. The offset is in etype units rel- ative to the current view. That is, holes are not counted when locating an offset. The data is taken out of those parts of the file speci- fied 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 _end as a suffix. These split collective routines are subject to the semantic rules described in Section 9.4.5 of the MPI-2 standard. ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ func- tions 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. 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 handler may be changed with MPI_File_set_errhandler; the predefined error handler MPI_ERRORS_ARE_FATAL may be used to make I/O errors fatal. Note that MPI does not guarantee that an MPI program can continue past an error. Open MPI 1.2 September 2006 MPI_File_read_at_all_begin(3OpenMPI)
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MPI_File_write_at(3OpenMPI) MPI_File_write_at(3OpenMPI) NAME
MPI_File_write_at - Writes a file at an explicitly specified offset (blocking, noncollective). SYNTAX
C Syntax #include <mpi.h> int MPI_File_write_at(MPI_File fh, MPI_Offset offset, void *buf, int count, MPI_Datatype datatype, MPI_Status *status) Fortran Syntax (see FORTRAN 77 NOTES) INCLUDE 'mpif.h' MPI_FILE_WRITE_AT(FH, OFFSET, BUF, COUNT, DATATYPE, STATUS, IERROR) <type> BUF(*) INTEGER FH, COUNT, DATATYPE, STATUS(MPI_STATUS_SIZE), IERROR INTEGER(KIND=MPI_OFFSET_KIND) OFFSET C++ Syntax #include <mpi.h> void MPI::File::Write_at(MPI::Offset offset, const void* buf, int count, const MPI::Datatype& datatype, MPI::Status& status) void MPI::File::Write_at(MPI::Offset offset, const void* buf, int count, const MPI::Datatype& datatype) INPUT PARAMETERS
fh File handle (handle). offset File offset (integer). buf Initial address of buffer (choice). count Number of elements in buffer (integer). datatype Data type of each buffer element (handle). OUTPUT PARAMETERS
status Status object (status). IERROR Fortran only: Error status (integer). DESCRIPTION
MPI_File_write_at attempts to write into the file associated 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 the file specified by the current view. MPI_File_write_at stores the number of datatype elements actually written in status. All other fields of status are undefined. It is erroneous to call this function if MPI_MODE_SEQUENTIAL mode was specified when the file was opened. 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. ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ func- tions 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. 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 handler may be changed with MPI_File_set_errhandler; the predefined error handler MPI_ERRORS_ARE_FATAL may be used to make I/O errors fatal. Note that MPI does not guarantee that an MPI program can continue past an error. SEE ALSO
MPI_File_iwrite_at MPI_File_write_at_all MPI_File_write_at_all_begin MPI_File_write_at_all_end Open MPI 1.2 September 2006 MPI_File_write_at(3OpenMPI)