NAME¶
MPI_Isend - Starts a standard-mode, nonblocking send.
SYNTAX¶
C Syntax¶
#include <mpi.h>
int MPI_Isend(void * buf, int count, MPI_Datatype datatype, int dest,
int tag, MPI_Comm comm, MPI_Request *request)
Fortran Syntax¶
INCLUDE 'mpif.h'
MPI_ISEND( BUF, COUNT, DATATYPE, DEST, TAG, COMM, REQUEST, IERROR)
<type> BUF(*)
INTEGER COUNT, DATATYPE, DEST, TAG, COMM, REQUEST, IERROR
C++ Syntax¶
#include <mpi.h>
Request Comm::Isend(const void* buf, int count, const
Datatype& datatype, int dest, int tag) const
- buf
- Initial address of send buffer (choice).
- count
- Number of elements in send buffer (integer).
- datatype
- Datatype of each send buffer element (handle).
- dest
- Rank of destination (integer).
- tag
- Message tag (integer).
- comm
- Communicator (handle).
OUTPUT PARAMETERS¶
- request
- Communication request (handle).
- IERROR
- Fortran only: Error status (integer).
DESCRIPTION¶
MPI_Isend starts a standard-mode, nonblocking send. 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.
A nonblocking send call indicates that the system may start copying data out of
the send buffer. The sender should not access any part of the send buffer
after a nonblocking send operation is called, until the send completes.
A send request can be determined being completed by calling the MPI_Wait,
MPI_Waitany, MPI_Test, or MPI_Testany with request returned by this function.
ERRORS¶
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.
SEE ALSO¶
MPI_Send MPI_Wait MPI_Waitany MPI_Test MPI_Testany