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<H1 id="MPI_Iscatterv">MPI_Iscatterv</H1>
Scatters a buffer in parts to all processes in a communicator in a nonblocking way
<H2>Synopsis</H2>
<PRE>
int MPI_Iscatterv(const void *sendbuf, const int sendcounts[], const int displs[],
MPI_Datatype sendtype, void *recvbuf, int recvcount, MPI_Datatype recvtype,
int root, MPI_Comm comm, MPI_Request * request)
</PRE>
<H2>Input Parameters</H2>
<DL>
<DT><B>sendbuf </B> <DD> address of send buffer (significant only at root) (choice)
<DT><B>sendcounts </B> <DD> non-negative integer array (of length group size) specifying the number of elements to send to each processor (significant only at root)
<DT><B>displs </B> <DD> integer array (of length group size). Entry i specifies the displacement (relative to sendbuf) from which to take the outgoing data to process i (significant only at root)
<DT><B>sendtype </B> <DD> data type of send buffer elements (significant only at root) (handle)
<DT><B>recvcount </B> <DD> number of elements in receive buffer (non-negative integer)
<DT><B>recvtype </B> <DD> data type of receive buffer elements (handle)
<DT><B>root </B> <DD> rank of sending process (integer)
<DT><B>comm </B> <DD> communicator (handle)
</DL>
<P>
<H2>Output Parameters</H2>
<DL>
<DT><B>recvbuf </B> <DD> starting address of the receive buffer (choice)
<DT><B>request </B> <DD> communication request (handle)
</DL>
<P>
<H2>Thread and Interrupt Safety</H2>
<P>
This routine is thread-safe. This means that this routine may be
safely used by multiple threads without the need for any user-provided
thread locks. However, the routine is not interrupt safe. Typically,
this is due to the use of memory allocation routines such as <tt>malloc
</tt>or other non-MPICH runtime routines that are themselves not interrupt-safe.
<P>
<H2>Notes for Fortran</H2>
All MPI routines in Fortran (except for <tt>MPI_WTIME</tt> and <tt>MPI_WTICK</tt>) have
an additional argument <tt>ierr</tt> at the end of the argument list. <tt>ierr
</tt>is an integer and has the same meaning as the return value of the routine
in C. In Fortran, MPI routines are subroutines, and are invoked with the
<tt>call</tt> statement.
<P>
All MPI objects (e.g., <tt>MPI_Datatype</tt>, <tt>MPI_Comm</tt>) are of type <tt>INTEGER
</tt>in Fortran.
<P>
<H2>Errors</H2>
<P>
All MPI routines (except <tt>MPI_Wtime</tt> and <tt>MPI_Wtick</tt>) return an error value;
C routines as the value of the function and Fortran routines in the last
argument. Before the value is returned, the current MPI error handler is
called. By default, this error handler aborts the MPI job. The error handler
may be changed with <tt>MPI_Comm_set_errhandler</tt> (for communicators),
<tt>MPI_File_set_errhandler</tt> (for files), and <tt>MPI_Win_set_errhandler</tt> (for
RMA windows). The MPI-1 routine <tt>MPI_Errhandler_set</tt> may be used but
its use is deprecated. The predefined error handler
<tt>MPI_ERRORS_RETURN</tt> may be used to cause error values to be returned.
Note that MPI does <em>not</em> guarentee that an MPI program can continue past
an error; however, MPI implementations will attempt to continue whenever
possible.
<P>
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