:ref:`MPI_File_read` - Reads a file starting at the location specified by the individual file pointer (blocking, noncollective).
#include <mpi.h>
int MPI_File_read(MPI_File fh, void *buf,
int count, MPI_Datatype datatype, MPI_Status *status)
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_FILE_READ(FH, BUF, COUNT,
DATATYPE, STATUS, IERROR)
<type> BUF(*)
INTEGER FH, COUNT, DATATYPE, STATUS(MPI_STATUS_SIZE),IERROR
USE mpi_f08
MPI_File_read(fh, buf, count, datatype, status, ierror)
TYPE(MPI_File), INTENT(IN) :: fh
TYPE(*), DIMENSION(..) :: buf
INTEGER, INTENT(IN) :: count
TYPE(MPI_Datatype), INTENT(IN) :: datatype
TYPE(MPI_Status) :: status
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
fh
: File handle (handle).count
: Number of elements in buffer (integer).datatype
: Data type of each buffer element (handle).
buf
: Initial address of buffer (integer).status
: Status object (status).ierror
: Fortran only: Error status (integer).
:ref:`MPI_File_read` attempts to read from the file associated with fh (at the current individual file pointer position maintained by the system) a total number of count data items having datatype type into the user's buffer buf. The data is taken out of those parts of the file specified by the current view. :ref:`MPI_File_read` stores the number of data-type elements actually read 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.