# MPI Point-to-point communication
**Point-to-point communication** sends messages between two processes. `MPI_Send` transmits a buffer to a target rank; `MPI_Recv` receives from a source rank. Both specify buffer, element count, datatype, peer rank, message tag, and communicator.

```c
if (rank == 0) {
    int x = 42;
    MPI_Send(&x, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
} else if (rank == 1) {
    int x;
    MPI_Recv(&x, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
    printf("received %d\n", x);
}
```

`MPI_ANY_SOURCE` and `MPI_ANY_TAG` are wildcards that match any sender or tag in `MPI_Recv`. When wildcards are used, the actual source, tag, and element count are returned in the `MPI_Status` struct. `MPI_Sendrecv` combines a send and a receive in a single call, which is the simplest way to avoid deadlock in patterns where every process must both send and receive simultaneously.