mpi_attr_get(3) [debian man page]

MPI_Attr_get(3) 							MPI							   MPI_Attr_get(3)

NAME

       MPI_Attr_get -  Retrieves attribute value by key

SYNOPSIS

       int MPI_Attr_get(MPI_Comm comm, int keyval, void *attr_value, int *flag)

INPUT PARAMETERS

       comm   - communicator to which attribute is attached (handle)
       keyval - key value (integer)

OUTPUT PARAMETERS

       attr_value
	      - attribute value, unless flag = false
       flag   - true if an attribute value was extracted;  false if no attribute is associated with the key

NOTES

       Attributes must be extracted from the same language as they were inserted in with MPI_ATTR_PUT .  The notes for C and Fortran below explain
       why.

NOTES FOR C

       Even though the attr_value arguement is declared as void * , it is really the address of a void pointer (i.e., a void ** ).  Using a void *
       , however, is more in keeping with C idiom and allows the pointer to be passed without additional casts.

THREAD AND INTERRUPT SAFETY

       This  routine  is  thread-safe.	This means that this routine may be safely used by multiple threads without the need for any user-provided
       thread locks.  However, the routine is not interrupt safe.  Typically, this is due to the use of memory allocation routines such as  malloc
       or other non-MPICH runtime routines that are themselves not interrupt-safe.

DEPRECATED FUNCTION

       The  MPI-2  standard  deprecated a number of routines because MPI-2 provides better versions.  This routine is one of those that was depre-
       cated.  The routine may continue to be used, but new code should use  the  replacement  routine.   The  replacement  for  this  routine	is
       MPI_Comm_get_attr .

NOTES FOR FORTRAN

       All  MPI  routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the end of the argument list.  ierr
       is an integer and has the same meaning as the return value of the routine in C.	In Fortran, MPI routines are subroutines, and are  invoked
       with the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.

       The attr_value in Fortran is a pointer to a Fortran integer, not a pointer to a void * .

ERRORS

       All  MPI  routines (except MPI_Wtime and MPI_Wtick ) return an error value; C routines as the value of the function and Fortran routines in
       the last argument.  Before the value is returned, the current MPI error handler is called.  By default, this error handler aborts  the  MPI
       job.   The  error  handler  may	be  changed  with  MPI_Comm_set_errhandler  (for  communicators), MPI_File_set_errhandler (for files), and
       MPI_Win_set_errhandler (for RMA windows).  The MPI-1 routine MPI_Errhandler_set may be used but its  use  is  deprecated.   The	predefined
       error handler MPI_ERRORS_RETURN may be used to cause error values to be returned.  Note that MPI does not guarentee that an MPI program can
       continue past an error; however, MPI implementations will attempt to continue whenever possible.

       MPI_SUCCESS
	      - No error; MPI routine completed successfully.
       MPI_ERR_COMM
	      - Invalid communicator.  A common error is to use a null communicator in a call (not even allowed in MPI_Comm_rank ).
       MPI_ERR_KEYVAL
	      - Invalid keyval

SEE ALSO

       MPI_Attr_put, MPI_Keyval_create, MPI_Attr_delete, MPI_Comm_get_attr

LOCATION

       attr_get.c

								     7/21/2010							   MPI_Attr_get(3)