Definition
MPI_Ssend is the synchronous blocking send (the capital 'S' standing for synchronous); it will block until the recipient has received the message. As a blocking send, MPI_Ssend guarantees that the buffer passed can be safely reused once MPI_Ssend returns. Also, this routine may be invoked implicitly by the standard blocking send (MPI_Send). Refer to MPI_Issend to see the non-blocking counterpart of this routine. Other blocking sends are MPI_Send, MPI_Bsend and MPI_Rsend.
int MPI_Ssend(const void* buffer,
int count,
MPI_Datatype datatype,
int recipient,
int tag,
MPI_Comm communicator);