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MPI_File_set_atomicity(3) man page (version 1.2.9)

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       MPI_File_set_atomicity  -  Sets  consistency  semantics for data-access
       operations (collective).


       C Syntax
           #include <mpi.h>
           int MPI_File_set_atomicity(MPI_File fh, int flag)

       Fortran Syntax
           INCLUDE 'mpif.h'
                  INTEGER    FH, FLAG, IERROR

C++ Syntax

       #include <mpi.h>
       void MPI::File::Set_atomicity(bool flag)


       fh        File handle (handle).

       flag      true to enable atomic mode, false to  enable  nonatomic  mode


       IERROR    Fortran only: Error status (integer).


       The  consistency  semantics for data-access operations using the set of
       file handles created by one collective MPI_File_open is set by  collec-
       tively  calling MPI_File_set_atomicity. All processes in the group must
       pass identical values for fh and flag.  If flag is true, atomic mode is
       set; if flag is false, nonatomic mode is set.

       The  default  value  on a call to MPI_File_open in Open MPI is true for
       jobs running on more than one node, false for jobs running on a  single
       SMP. For more information, see the MPI-2 standard.


       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.

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