NAME

MPI_Get_count - Gets number of data type elements successfully transferred in a message

SYNOPSIS

#include <mpi.h> 
int MPI_Get_count(MPI_Status *status , MPI_Datatype datatype , int *count ); 
#include <pmpi.h> 
int PMPI_Get_count(MPI_Status *status , MPI_Datatype datatype , int *count ); 

INPUT PARAMETERS

status - request status (structure)

datatype - type of data in message (handle)

OUTPUT PARAMETER

count - number of elements transferred (integer).

DESCRIPTION

The MPI_Get_count() function is used to determine how many elements of type datatype were transferred in a message using a successfully completed message status .

If the datatype is "empty", with no data such as MPI_UB then this function will always return a count of zero.

Otherwise the value returned will be equal to the size of the message transferred in bytes ( status->size ) divided by the size of the datatype in bytes. If this does not work out to be a whole number, then count is set to be MPI_UNDEFINED.

PMPI_Get_count() is the profiling version of this function.

ERRORS

All MPI routines except for MPI_Wtime and MPI_Wtick return an error value. The the current MPI error handler is invoked if this return value is not MPI_SUCCESS. The default error handler aborts, but this may be changed with by using the MPI_Errhandler_set() function. The predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned instead. Note that MPI does not guarentee that an MPI program can continue past an error. In this implementation, all errors except MPI_ERR_INTERN or MPI_ERR_OTHER should always be recoverable.

MPI_SUCCESS - No error;

MPI_ERR_TYPE - Invalid data type;

MPI_ERR_ARG - Invalid status pointer;

MPI_ERR_COUNT - Invalid count pointer.

SEE ALSO

MPI_Test (3) MPI_Wait (3) MPI_Test_cancelled (3) MPI_Get_elements (3)

• Lockless
• MPI Documentation
• MPI_Get_count