.\" Man page generated from reStructuredText. . .TH "MPI_FILE_SET_VIEW" "3" "Jul 22, 2024" "" "Open MPI" . .nr rst2man-indent-level 0 . .de1 rstReportMargin \\$1 \\n[an-margin] level \\n[rst2man-indent-level] level margin: \\n[rst2man-indent\\n[rst2man-indent-level]] - \\n[rst2man-indent0] \\n[rst2man-indent1] \\n[rst2man-indent2] .. .de1 INDENT .\" .rstReportMargin pre: . RS \\$1 . nr rst2man-indent\\n[rst2man-indent-level] \\n[an-margin] . nr rst2man-indent-level +1 .\" .rstReportMargin post: .. .de UNINDENT . RE .\" indent \\n[an-margin] .\" old: \\n[rst2man-indent\\n[rst2man-indent-level]] .nr rst2man-indent-level -1 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]] .in \\n[rst2man-indent\\n[rst2man-indent-level]]u .. .sp \fI\%MPI_File_set_view\fP — Changes process’s view of data in file (collective). .SH SYNTAX .SS C Syntax .INDENT 0.0 .INDENT 3.5 .sp .nf .ft C #include int MPI_File_set_view(MPI_File fh, MPI_Offset disp, MPI_Datatype etype, MPI_Datatype filetype, const char *datarep, MPI_Info info) .ft P .fi .UNINDENT .UNINDENT .SS Fortran Syntax .INDENT 0.0 .INDENT 3.5 .sp .nf .ft C USE MPI ! or the older form: INCLUDE \(aqmpif.h\(aq MPI_FILE_SET_VIEW(FH, DISP, ETYPE, FILETYPE, DATAREP, INFO, IERROR) INTEGER FH, ETYPE, FILETYPE, INFO, IERROR CHARACTER*(*) DATAREP INTEGER(KIND=MPI_OFFSET_KIND) DISP .ft P .fi .UNINDENT .UNINDENT .SS Fortran 2008 Syntax .INDENT 0.0 .INDENT 3.5 .sp .nf .ft C USE mpi_f08 MPI_File_set_view(fh, disp, etype, filetype, datarep, info, ierror) TYPE(MPI_File), INTENT(IN) :: fh INTEGER(KIND=MPI_OFFSET_KIND), INTENT(IN) :: disp TYPE(MPI_Datatype), INTENT(IN) :: etype, filetype CHARACTER(LEN=*), INTENT(IN) :: datarep TYPE(MPI_Info), INTENT(IN) :: info INTEGER, OPTIONAL, INTENT(OUT) :: ierror .ft P .fi .UNINDENT .UNINDENT .SH INPUT/OUTPUT PARAMETER .INDENT 0.0 .IP \(bu 2 \fBfh\fP: File handle (handle). .UNINDENT .SH INPUT PARAMETERS .INDENT 0.0 .IP \(bu 2 \fBdisp\fP: Displacement (integer). .IP \(bu 2 \fBetype\fP: Elementary data type (handle). .IP \(bu 2 \fBfiletype\fP: File type (handle). See Restrictions, below. .IP \(bu 2 \fBdatarep\fP: Data representation (string). .IP \(bu 2 \fBinfo\fP: Info object (handle). .UNINDENT .SH OUTPUT PARAMETER .INDENT 0.0 .IP \(bu 2 \fBierror\fP: Fortran only: Error status (integer). .UNINDENT .SH DESCRIPTION .sp The \fI\%MPI_File_set_view\fP routine changes the process’s view of the data in the file — the beginning of the data accessible in the file through that view is set to \fIdisp;\fP the type of data is set to \fIetype;\fP and the distribution of data to processes is set to \fIfiletype.\fP In addition, \fI\%MPI_File_set_view\fP resets the independent file pointers and the shared file pointer to zero. \fI\%MPI_File_set_view\fP is collective across the \fIfh\fP; all processes in the group must pass identical values for \fIdatarep\fP and provide an \fIetype\fP with an identical extent. The values for \fIdisp\fP, \fIfiletype\fP, and \fIinfo\fP may vary. It is erroneous to use the shared file pointer data\-access routines unless identical values for \fIdisp\fP and \fIfiletype\fP are also given. The data types passed in \fIetype\fP and \fIfiletype\fP must be committed. .sp The \fIdisp\fP displacement argument specifies the position (absolute offset in bytes from the beginning of the file) where the view begins. .sp The \fI\%MPI_File_set_view\fP interface allows the user to pass a data\-representation string to MPI I/O via the \fIdatarep\fP argument. To obtain the default value pass the value “native”. The user can also pass information via the \fIinfo\fP argument. See the \fI\%HINTS section\fP for a list of hints that can be set. .SH HINTS .sp The following hints can be used as values for the \fIinfo\fP argument. .sp \fBSETTABLE HINTS\fP .INDENT 0.0 .IP \(bu 2 \fBMPI_INFO_NULL\fP .IP \(bu 2 \fBshared_file_timeout\fP: Amount of time (in seconds) to wait for access to the shared file pointer before exiting with \fBMPI_ERR_TIMEDOUT\fP\&. .IP \(bu 2 \fBrwlock_timeout\fP: Amount of time (in seconds) to wait for obtaining a read or write lock on a contiguous chunk of a UNIX file before exiting with \fBMPI_ERR_TIMEDOUT\fP\&. .IP \(bu 2 \fBnoncoll_read_bufsize\fP: Maximum size of the buffer used by MPI I/O to satisfy read requests in the noncollective data\-access routines. .sp \fBNOTE:\fP .INDENT 2.0 .INDENT 3.5 A buffer size smaller than the distance (in bytes) in a UNIX file between the first byte and the last byte of the access request causes MPI I/O to iterate and perform multiple UNIX \fBread()\fP or \fBwrite()\fP calls. If the request includes multiple noncontiguous chunks of data, and the buffer size is greater than the size of those chunks, then the UNIX \fBread()\fP or \fBwrite()\fP (made at the MPI I/O level) will access data not requested by this process in order to reduce the total number of \fBwrite()\fP calls made. If this is not desirable behavior, you should reduce this buffer size to equal the size of the contiguous chunks within the aggregate request. .UNINDENT .UNINDENT .IP \(bu 2 \fBnoncoll_write_bufsize\fP: Maximum size of the buffer used by MPI I/O to satisfy write requests in the noncollective data\-access routines. .sp See the above note in \fBnoncoll_read_bufsize\fP\&. .IP \(bu 2 \fBcoll_read_bufsize\fP: Maximum size of the buffer used by MPI I/O to satisfy read requests in the collective data\-access routines. .sp See the above note in \fBnoncoll_read_bufsize\fP\&. .IP \(bu 2 \fBcoll_write_bufsize\fP: Maximum size of the buffer used by MPI I/O to satisfy write requests in the collective data\-access routines. .sp See the above note in \fBnoncoll_read_bufsize\fP\&. .IP \(bu 2 \fBmpiio_concurrency\fP: (boolean) controls whether nonblocking I/O routines can bind an extra thread to an LWP. .IP \(bu 2 \fBmpiio_coll_contiguous\fP: (boolean) controls whether subsequent collective data accesses will request collectively contiguous regions of the file. .UNINDENT .sp \fBNON\-SETTABLE HINTS\fP .INDENT 0.0 .IP \(bu 2 \fBfilename\fP: Access this hint to get the name of the file. .UNINDENT .SH ERRORS .sp Almost all MPI routines return an error value; C routines as the return result of the function and Fortran routines in the last argument. .sp Before the error value is returned, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. If no communication object is associated with the MPI call, then the call is considered attached to MPI_COMM_SELF and will call the associated MPI error handler. When MPI_COMM_SELF is not initialized (i.e., before \fI\%MPI_Init\fP/\fI\%MPI_Init_thread\fP, after \fI\%MPI_Finalize\fP, or when using the Sessions Model exclusively) the error raises the initial error handler. The initial error handler can be changed by calling \fI\%MPI_Comm_set_errhandler\fP on MPI_COMM_SELF when using the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info key to \fI\%MPI_Comm_spawn\fP/\fI\%MPI_Comm_spawn_multiple\fP\&. If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all other MPI functions. .sp Open MPI includes three predefined error handlers that can be used: .INDENT 0.0 .IP \(bu 2 \fBMPI_ERRORS_ARE_FATAL\fP Causes the program to abort all connected MPI processes. .IP \(bu 2 \fBMPI_ERRORS_ABORT\fP An error handler that can be invoked on a communicator, window, file, or session. When called on a communicator, it acts as if \fI\%MPI_Abort\fP was called on that communicator. If called on a window or file, acts as if \fI\%MPI_Abort\fP was called on a communicator containing the group of processes in the corresponding window or file. If called on a session, aborts only the local process. .IP \(bu 2 \fBMPI_ERRORS_RETURN\fP Returns an error code to the application. .UNINDENT .sp MPI applications can also implement their own error handlers by calling: .INDENT 0.0 .IP \(bu 2 \fI\%MPI_Comm_create_errhandler\fP then \fI\%MPI_Comm_set_errhandler\fP .IP \(bu 2 \fI\%MPI_File_create_errhandler\fP then \fI\%MPI_File_set_errhandler\fP .IP \(bu 2 \fI\%MPI_Session_create_errhandler\fP then \fI\%MPI_Session_set_errhandler\fP or at \fI\%MPI_Session_init\fP .IP \(bu 2 \fI\%MPI_Win_create_errhandler\fP then \fI\%MPI_Win_set_errhandler\fP .UNINDENT .sp Note that MPI does not guarantee that an MPI program can continue past an error. .sp See the \fI\%MPI man page\fP for a full list of \fI\%MPI error codes\fP\&. .sp See the Error Handling section of the MPI\-3.1 standard for more information. .SH COPYRIGHT 2003-2024, The Open MPI Community .\" Generated by docutils manpage writer. .