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MPI_Waitany(3) MPI MPI_Waitany(3)

NAME

MPI_Waitany - Waits for any specified MPI Request to complete

SYNOPSIS



int MPI_Waitany(int count, MPI_Request array_of_requests[], int *indx,
MPI_Status *status)










INPUT PARAMETERS



  

  
- count (non-negative integer)
    

  








INPUT/OUTPUT PARAMETERS



  

  
- array of requests (handle)
    

  








OUTPUT PARAMETERS



  

  
- index of handle for operation that completed (integer)

  

  
- status object (Status)
    

  








NOTES


If all of the requests are MPI_REQUEST_NULL , then
    indx is returned as MPI_UNDEFINED , and status is
    returned as an empty status.


While it is possible to list a request handle more than once in
    the array_of_requests, such an action is considered erroneous and may cause
    the program to unexecpectedly terminate or produce incorrect results.








NOTES ON THE MPI_STATUS ARGUMENT


The MPI_ERROR field of the status return is only set if the
    return from the MPI routine is MPI_ERR_IN_STATUS . That error class
    is only returned by the routines that take an array of status arguments (
    MPI_Testall , MPI_Testsome , MPI_Waitall , and
    MPI_Waitsome ). In all other cases, the value of the MPI_ERROR
    field in the status is unchanged. See section 3.2.5 in the MPI-1.1
    specification for the exact text.


For send operations, the only use of status is for
    MPI_Test_cancelled or in the case that there is an error in one of
    the four routines that may return the error class MPI_ERR_IN_STATUS ,
    in which case the MPI_ERROR field of status will be set. In that
    case, the value will be set to MPI_SUCCESS for any send or receive
    operation that completed successfully, or MPI_ERR_PENDING for any
    operation which has neither failed nor completed.








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.








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.








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 guarantee that an MPI
    program can continue past an error; however, MPI implementations will
    attempt to continue whenever possible.





  

  
- No error; MPI routine completed successfully.

  

  
- Invalid argument. Some argument is invalid and is not identified by a
      specific error class (e.g., MPI_ERR_RANK ).

  

  
- Invalid count argument. Count arguments must be non-negative; a count of
      zero is often valid.

  

  
- Invalid MPI_Request . Either null or, in the case of a
      MPI_Start or MPI_Startall , not a persistent request.

  

  
- Other error; use MPI_Error_string to get more information about
      this error code.
    

  









  

    2/9/2024