MPI_Grequest_complete - Reports that a generalized request is
int MPI_Grequest_complete(MPI_Request request)
INTEGER REQUEST, IERROR
request Generalized request (handle).
IERROR Fortran only: Error status (integer).
MPI_Grequest_complete informs MPI that the operations represented by
the generalized request request are complete. A call to
MPI_Wait(request, status) will return, and a call to MPI_Test(request,
flag, status) will return flag=true only after a call to
MPI_Grequest_complete has declared that these operations are complete.
MPI imposes no restrictions on the code executed by the callback
functions. However, new nonblocking operations should be defined so
that the general semantic rules about MPI calls such as MPI_Test,
MPI_Request_free, or MPI_Cancel still hold. For example, all these
calls are supposed to be local and nonblocking. Therefore, the callback
functions query_fn, free_fn, or cancel_fn should invoke blocking MPI
communication calls only if the context is such that these calls are
guaranteed to return in finite time. Once MPI_Cancel has been invoked,
the canceled operation should complete in finite time, regardless of
the state of other processes (the operation has acquired "local"
semantics). It should either succeed or fail without side-effects. The
user should guarantee these same properties for newly defined
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.
Before the error value is returned, the current MPI error handler is
called. By default, this error handler aborts the MPI job, except for
I/O function errors. The error handler may be changed with
MPI_Comm_set_errhandler; 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.