NAME

       MPI_Waitany -  Waits for any specified send or receive to complete

SYNOPSIS

       #include <mpi.h>
       int MPI_Waitany(int count, MPI_Request *reqs, int *index,
                      MPI_Status *stat)

INPUT PARAMETERS

       count  - list length (integer)
       reqs   - 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 .

       stat   - status object (Status), or the MPI constant MPI_STATUS_IGNORE

NOTES

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

NOTE ON STATUS FOR SEND OPERATIONS

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

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

       If  an  error occurs in an MPI function, the current MPI error handler is called to handle
       it.  By default, this error handler aborts the MPI job.  The error handler may be  changed
       with  MPI_Errhandler_set  ;  the predefined error handler MPI_ERRORS_RETURN may be used to
       cause error values to be returned (in C and Fortran; this error handler is less useful  in
       with  the  C++  MPI  bindings.   The predefined error handler MPI::ERRORS_THROW_EXCEPTIONS
       should be used in C++ if the error value needs to be recovered).  Note that MPI  does  not
       guarantee that an MPI program can continue past an error.

       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.  The C++ bindings for
       MPI  do  not  return  error  values;  instead,  error  values are communicated by throwing
       exceptions of type MPI::Exception (but not by default).  Exceptions are only thrown if the
       error value is not MPI::SUCCESS .

       Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI functions will return
       upon an error, there will be no way to recover what the actual error value was.
       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_REQUEST
              - Invalid MPI_Request ; either null  or,  MPI_REQUEST_NULL  ,  in  the  case  of  a
              MPI_Start or MPI_Startall , not a persistent request.
       MPI_ERR_COUNT
              - Invalid count argument.  Count arguments must be non-negative; a count of zero is
              often valid.
       MPI_ERR_ARG
              - Invalid argument.  Some argument is invalid and is not identified by  a  specific
              error class.  This is typically a NULL pointer or other such error.

MORE INFORMATION

       For  more information, please see the official MPI Forum web site, which contains the text
       of both the MPI-1 and MPI-2 standards.  These documents contain detailed information about
       each MPI function (most of which is not duplicated in these man pages).

       http://www.mpi-forum.org/

ACKNOWLEDGEMENTS

       The  LAM  Team  would  like the thank the MPICH Team for the handy program to generate man
       pages  ("doctext"  from  ftp://ftp.mcs.anl.gov/pub/sowing/sowing.tar.gz  ),  the   initial
       formatting, and some initial text for most of the MPI-1 man pages.

LOCATION

       waitany.c