MPI_Testany - Tests for completion of any one previously initiated communication in a list.
19.2.376.1.1. C Syntax
#include <mpi.h> int MPI_Testany(int count, MPI_Request array_of_requests, int *index, int *flag, MPI_Status *status)
19.2.376.1.2. Fortran Syntax
USE MPI ! or the older form: INCLUDE 'mpif.h' MPI_TESTANY(COUNT, ARRAY_OF_REQUESTS, INDEX, FLAG, STATUS, IERROR) LOGICAL FLAG INTEGER COUNT, ARRAY_OF_REQUESTS(*), INDEX INTEGER STATUS(MPI_STATUS_SIZE), IERROR
19.2.376.1.3. Fortran 2008 Syntax
USE mpi_f08 MPI_Testany(count, array_of_requests, index, flag, status, ierror) INTEGER, INTENT(IN) :: count TYPE(MPI_Request), INTENT(INOUT) :: array_of_requests(count) INTEGER, INTENT(OUT) :: index LOGICAL, INTENT(OUT) :: flag TYPE(MPI_Status) :: status INTEGER, OPTIONAL, INTENT(OUT) :: ierror
19.2.376.2. INPUT PARAMETERS
count: List length (integer).
array_of_requests: Array of requests (array of handles).
19.2.376.3. OUTPUT PARAMETERS
index: Index of operation that completed, or
MPI_UNDEFINEDif none completed (integer).
flag: True if one of the operations is complete (logical).
status: Status object (status).
ierror: Fortran only: Error status (integer).
MPI_Testany tests for completion of either one or none of the operations
associated with active handles. In the former case, it returns flag =
true, returns in index the index of this request in the array, and
returns in status the status of that operation; if the request was
allocated by a nonblocking communication call then the request is
deallocated and the handle is set to
MPI_REQUEST_NULL. (The array is
indexed from 0 in C, and from 1 in Fortran.) In the latter case (no
operation completed), it returns flag = false, returns a value of
MPI_UNDEFINED in index, and status is undefined.
The array may contain null or inactive handles. If the array contains no
active handles then the call returns immediately with flag = true,
MPI_UNDEFINED, and an empty status.
If the array of requests contains active handles then the execution of
MPI_Testany(count, array_of_requests, index, status) has the same effect
as the execution of
MPI_Test(&array_of_requests[i], flag, status),
for i=0,1,…,count-1, in some arbitrary order, until one
flag = true, or all fail. In the former case, index is
set to the last value of i, and in the latter case, it is set to
MPI_UNDEFINED. MPI_Testany with an array containing one active entry is
equivalent to MPI_Test.
If your application does not need to examine the status field, you can
save resources by using the predefined constant
MPI_STATUS_IGNORE as a
special value for the status argument.
Almost all MPI routines return an error value; C routines as the return result of the function and Fortran routines in the last argument.
Before the error value is returned, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. If no communication object is associated with the MPI call, then the call is considered attached to MPI_COMM_SELF and will call the associated MPI error handler. When MPI_COMM_SELF is not initialized (i.e., before MPI_Init/MPI_Init_thread, after MPI_Finalize, or when using the Sessions Model exclusively) the error raises the initial error handler. The initial error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info key to MPI_Comm_spawn/MPI_Comm_spawn_multiple. If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all other MPI functions.
Open MPI includes three predefined error handlers that can be used:
MPI_ERRORS_ARE_FATALCauses the program to abort all connected MPI processes.
MPI_ERRORS_ABORTAn error handler that can be invoked on a communicator, window, file, or session. When called on a communicator, it acts as if MPI_Abort was called on that communicator. If called on a window or file, acts as if MPI_Abort was called on a communicator containing the group of processes in the corresponding window or file. If called on a session, aborts only the local process.
MPI_ERRORS_RETURNReturns an error code to the application.
MPI applications can also implement their own error handlers by calling:
MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init
Note that MPI does not guarantee that an MPI program can continue past an error.
See the MPI man page for a full list of MPI error codes.
See the Error Handling section of the MPI-3 standard for more information.
Note that per MPI-1 section 3.2.5, MPI errors on requests passed to
MPI_Testany do not set the
status.MPI_ERROR field in the returned
status. The error code is passed to the back-end error handler and may
be passed back to the caller through the return value of MPI_Testany if
the back-end error handler returns it. The pre-defined MPI error handler
MPI_ERRORS_RETURN exhibits this behavior, for example.