Waits for any specified send or receive to complete


#include "mpi.h"
int MPI_Waitany(count, array_of_requests, index, status )
int         count;
MPI_Request array_of_requests[];
int         *index;
MPI_Status  *status;

Input Parameters

count list length (integer)
array_of_requests array of requests (array of handles)

Output Parameters

index index of handle for operation that completed (integer). In the range 0 to count-1. In Fortran, the range is 1 to count.
status status object (Status)

Note on status for send operations

For send operations, the only use of status is for MPI_Test_cancelled orin the case that there is an error, in which case the MPI_ERROR field ofstatus will be set.

Notes for Fortran

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

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


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 lastargument. Before the value is returned, the current MPI error handler iscalled. By default, this error handler aborts the MPI job. The error handlermay be changed with MPI_Errhandler_set; the predefined error handlerMPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue pastan error.

No error; MPI routine completed successfully.
Invalid MPI_Request. Either null or, in the case of a MPI_Start or MPI_Startall, not a persistent request.
Invalid argument. Some argument is invalid and is not identified by a specific error class (e.g., MPI_ERR_RANK).