NAME
MMPPIIFFiilleerreeaaddaattaallllbbeeggiinn - Reads a file at explicitly specified off-
sets; beginning part of a split collective routine (nonblocking). SSYYNNTTAAXX C Syntax#include
int MPIFilereadatallbegin(MPIFile fh, MPIOffset offset, void *buf, int count, MPIDatatype datatype)Fortran Syntax (see FORTRAN 77 NOTES)
INCLUDE 'mpif.h' MPIFILEREADATALLBEGIN(FH, OFFSET, BUF,COUNT, DATATYPE, IERROR)
BUF(*) INTEGER FH, COUNT, DATATYPE, IERROR
INTEGER(KIND=MPIOFFSETKIND) OFFSET CC++++ SSyynnttaaxx#include
void MPI::File::Readatallbegin(MPI::Offset offset, void* buf, int count, const MPI::Datatype& datatype) IINNPPUUTT PPAARRAAMMEETTEERRSS fh File handle (handle). offset File offset (integer). count Number of elements in buffer (integer). datatype Data type of each buffer element. OOUUTTPPUUTT PPAARRAAMMEETTEERRSS buf Initial address of buffer (choice).IERROR Fortran only: Error status (integer).
DESCRIPTION
MPIFilereadatallbegin 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 relative 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 specified by the current view. FFOORRTTRRAANN 7777 NNOOTTEESS The MPI standard prescribes portable Fortran syntax for the OFFSETargument only for Fortran 90. FORTRAN 77 users may use the non-portable
syntax INTEGER*MPIOFFSETKIND OFFSET where MPIOFFSETKIND is a constant defined in mpif.h and gives the length of the declared integer in bytes. NNOOTTEESS All the nonblocking collective routines for data access are "split" into two routines, each with begin or end as a suffix. These splitcollective routines are subject to the semantic rules described in Sec-
tion 9.4.5 of the MPI-2 standard.
EERRRROORRSS Almost all MPI routines return an error value; C routines as the valueof the function and Fortran routines in the last argument. C++ func-
tions do not return errors. If the default error handler is set toMPI::ERRORSTHROWEXCEPTIONS, 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 setto MPIERRORSRETURN. The error handler may be changed with
MPIFileseterrhandler; the predefined error handlerMPIERRORSAREFATAL 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 2M0P0I6Filereadatallbegin(3OpenMPI)