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MPI_Grequest_complete(3) man page (version 3.0.0)

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MPI_Grequest_complete - Reports that a generalized request is complete.


C Syntax

#include <mpi.h>
int MPI_Grequest_complete(MPI_Request request)

Fortran Syntax

! or the older form: INCLUDE ’mpif.h’

Fortran 2008 Syntax

USE mpi_f08
MPI_Grequest_complete(request, ierror)
    TYPE(MPI_Request), INTENT(IN) :: request

Input/Output Parameter

Generalized request (handle).

Output Parameter

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 operations.


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.

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