MPI_Start - Initiates a communication using a persistent request
int MPI_Start(MPI_Request *request)
INTEGER REQUEST, IERROR
request Communication request (handle).
IERROR Fortran only: Error status (integer).
A communication (send or receive) that uses a persistent request is
initiated by the function MPI_Start.
The argument, request, is a handle returned by one of the persistent
communication-request initialization functions (MPI_Send_init,
MPI_Bsend_init, MPI_Ssend_init, MPI_Rsend_init, MPI_Recv_init). The
associated request should be inactive and becomes active once the call
If the request is for a send with ready mode, then a matching receive
should be posted before the call is made. From the time the call is
made until after the operation completes, the communication buffer
should not be accessed.
The call is local, with semantics similar to the nonblocking
communication operations (see Section 3.7 in the MPI-1 Standard,
"Nonblocking Communication.") That is, a call to MPI_Start with a
request created by MPI_Send_init starts a communication in the same
manner as a call to MPI_Isend; a call to MPI_Start with a request
created by MPI_Bsend_init starts a communication in the same manner as
a call to MPI_Ibsend; and so on.
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.