Index of operation that completed, or MPI_UNDEFINED if none completed
(integer).
.TP 1i
flag
True if one of the operations is complete (logical).
.TP 1i
status
Status object (status).
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.TP 1i
IERROR
Fortran only: Error status (integer).
.SH DESCRIPTION
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MPI_Testany tests for completion of either one or none of the operations associated with active handles. In the former case, it returns \fIflag\fP = true, returns in \fIindex\fP the index of this request in the array, and returns in \fIstatus\fP 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 \fIflag\fP = false, returns a value of MPI_UNDEFINED in \fIindex\fP, and \fIstatus\fP is undefined.
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The array may contain null or inactive handles. If the array contains no active handles then the call returns immediately with \fIflag\fP = true, \fIindex\fP = MPI_UNDEFINED, and an empty \fIstatus\fP.
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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(&\fIarray_of_requests[i\fP], \fIflag\fP, \fIstatus\fP), for \fIi\fP=0,1,...,count-1, in some arbitrary order, until one call returns \fIflag\fP = true, or all fail. In the former case, \fIindex\fP is set to the last value of \fIi\fP, 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.
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If your application does not need to examine the \fIstatus\fP field, you can save resources by using the predefined constant MPI_STATUS_IGNORE as a special value for the \fIstatus\fP argument.
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ functions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism will be used to throw an MPI::Exception object.
