.TH MPI_Get_count 3 "11/12/2019" " " "MPI"

.SH NAME

MPI_Get_count \-  Gets the number of "top level" elements 

.SH SYNOPSIS

.nf

int MPI_Get_count(const MPI_Status * status, MPI_Datatype datatype, int *count)

.fi

.SH INPUT PARAMETERS

.PD 0

.TP

.B status 

- return status of receive operation (Status)

.PD 1

.PD 0

.TP

.B datatype 

- datatype of each receive buffer element (handle)

.PD 1

.SH OUTPUT PARAMETERS

.PD 0

.TP

.B count 

- number of received elements (integer)

Notes:

If the size of the datatype is zero, this routine will return a count of

zero.  If the amount of data in 

.I status

is not an exact multiple of the

size of 

.I datatype

(so that 

.I count

would not be integral), a 

.I count

of

.I MPI_UNDEFINED

is returned instead.

.PD 1

.SH NOTES FOR FORTRAN

All MPI routines in Fortran (except for 

.I MPI_WTIME

and 

.I MPI_WTICK

) have

an additional argument 

.I ierr

at the end of the argument list.  

.I 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

.I call

statement.

All MPI objects (e.g., 

.I MPI_Datatype

, 

.I MPI_Comm

) are of type 

.I INTEGER

in Fortran.

.SH ERRORS

All MPI routines (except 

.I MPI_Wtime

and 

.I 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 

.I MPI_Comm_set_errhandler

(for communicators),

.I MPI_File_set_errhandler

(for files), and 

.I MPI_Win_set_errhandler

(for

RMA windows).  The MPI-1 routine 

.I MPI_Errhandler_set

may be used but

its use is deprecated.  The predefined error handler

.I MPI_ERRORS_RETURN

may be used to cause error values to be returned.

Note that MPI does 

.B not

guarentee that an MPI program can continue past

an error; however, MPI implementations will attempt to continue whenever

possible.

.PD 0

.TP

.B MPI_SUCCESS 

- No error; MPI routine completed successfully.

.PD 1

.PD 0

.TP

.B MPI_ERR_TYPE 

- Invalid datatype argument.  Additionally, this error can

occur if an uncommitted MPI_Datatype (see 

.I MPI_Type_commit

) is used

in a communication call.

.PD 1