Request Comm::Irecv(void* \fIbuf\fP, int \fIcount\fP, const Datatype&
\fIdatatype\fP, int \fIsource\fP, int \fItag\fP) const
.SHINPUTPARAMETERS
.ftR
.TP1i
buf
Initial address of receive buffer (choice).
.TP1i
count
Number of elements in receive buffer (integer).
.TP1i
datatype
Datatype of each receive buffer element (handle).
.TP1i
source
Rank of source (integer).
.TP1i
tag
Message tag (integer).
.TP1i
comm
Communicator (handle).
.SHOUTPUTPARAMETERS
.ftR
.TP1i
request
Communication request (handle).
.ftR
.TP1i
IERROR
Fortran only: Error status (integer).
.SHDESCRIPTION
.ftR
Nonblocking calls allocate a communication request object and associate it with the request handle (the argument request). The request can be used later to query the status of the communication or wait for its completion.
.sp
A nonblocking receive call indicates that the system may start writing data into the receive buffer. The receiver should not access any part of the receive buffer after a nonblocking receive operation is called, until the receive completes.
A receive request can be determined being completed by calling the MPI_Wait, MPI_Waitany, MPI_Test, or MPI_Testany with request returned by this function.
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.
.sp
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.