ph vid
#include <mpi.h>
int MPI_File_open(MPI_Comm comm, const char *filename,
int amode, MPI_Info info,
MPI_File *fh)
//MPI_File_open opens the file identified by the filename filename on all
//processes in the comm communicator group.
//MPI_File_open is a collective routine;
//all processes must provide the same value for amode,
//and all processes must provide filenames that reference the same file
//which are textually identical