[mpich-discuss] Problems with MPI Romio code

[Rajeev Thakur]

MPI-IO writes files in binary, not ASCII text. So you won't be able to
read them in an editor.

Rajeev
 

> -----Original Message-----
> From: mpich-discuss-bounces at mcs.anl.gov 
> [mailto:mpich-discuss-bounces at mcs.anl.gov] On Behalf Of shankha
> Sent: Thursday, July 01, 2010 1:02 AM
> To: mpich-discuss at mcs.anl.gov
> Subject: [mpich-discuss] Problems with MPI Romio code
> 
> Hi,
> I am trying to open a File through the MPI_File_open and 
> write to the file using MPI_File_write.
> Though all the calls seem to work fine when i try to open the 
> file in a editor I see junk.
> I couldn't understand the reason why the file ( testfile ) to 
> which I am writing the array buf doesn't have the correct values.
> 
> MPI Version : mpicc for MPICH2 version 1.2.1p1, gcc version 
> 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
> 
> following is piece of code :
> #include <stdio.h>
> #include <mpi.h>
> #include <stdlib.h>
> #include <string.h>
> #include <assert.h>
> #include <stdbool.h>
> 
> #define BUF_SIZE 3
> 
> int
> main ( int argc , char **argv )
> {
>   int myrank , size , i = 0;
>   MPI_File thefile;
>   int buf [ BUF_SIZE ];
>   MPI_Init(&argc, &argv);
>   MPI_Comm_rank ( MPI_COMM_WORLD, &myrank );
>   MPI_Comm_size ( MPI_COMM_WORLD, &size );
> 
>   for ( i = 0 ; i < BUF_SIZE ; i++ )
>     buf [ i ] = 9;
> 
>   for ( i = 0 ; i < BUF_SIZE; i++ )
>      buf [ i ] = myrank * BUF_SIZE + i;
>   MPI_File_open ( MPI_COMM_WORLD, "testfile", MPI_MODE_CREATE 
> | MPI_MODE_WRONLY,
>                     MPI_INFO_NULL, &thefile );
>   MPI_File_set_view ( thefile, myrank * BUF_SIZE *  sizeof ( 
> int ), MPI_INT,
>                       MPI_INT, "native", MPI_INFO_NULL );
>   MPI_File_write ( thefile, buf, BUF_SIZE, MPI_INT, 
> MPI_STATUS_IGNORE );
>   MPI_File_close ( &thefile );
>   MPI_Finalize ();
>   return 0;
> 
> }
> 
> Thanks for your help.
> Thanks
> Shankha
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