int MPI_Gather (
    const void *sendbuf, int sendcount, MPI_Datatype sendtype,
    void *recvbuf, int recvcount, MPI_Datatype recvtype,
    int root, MPI_Comm comm);
int MPI_Gather_c(
    const void *sendbuf, MPI_Count sendcount, MPI_Datatype sendtype,
    void *recvbuf, MPI_Count recvcount, MPI_Datatype recvtype,
    int root, MPI_Comm comm);

int MPI_Gatherv (
    const void *sendbuf, int sendcount, MPI_Datatype sendtype,
    void *recvbuf, const int recvcounts [], const int displs [], MPI_Datatype recvtype,
    int root, MPI_Comm comm);
int MPI_Gatherv_c (...);

int MPI_Igather (
    const void *sendbuf, int sendcount, MPI_Datatype sendtype,
    void *recvbuf, int recvcount, MPI_Datatype recvtype,
    int root, MPI_Comm comm,
    MPI_Request *request);
int MPI_Igather_c (...);

int MPI_Igatherv (
    const void *sendbuf, int sendcount, MPI_Datatype sendtype,
    void *recvbuf, const int recvcounts [], const int displs [],
    MPI_Datatype recvtype, int root, MPI_Comm comm,
    MPI_Request *request);
int MPI_Igatherv_c (...);

int MPI_Gather_init (
    const void *sendbuf, int sendcount, MPI_Datatype sendtype,
    void *recvbuf, int recvcount, MPI_Datatype recvtype,
    int root, MPI_Comm comm, MPI_Info info,
    MPI_Request *request);
int MPI_Gather_init_c (...);

int MPI_Gatherv_init (
    const void *sendbuf, int sendcount, MPI_Datatype sendtype,
    void *recvbuf, const int recvcounts [], const int displs [], MPI_Datatype recvtype,
    int root, MPI_Comm comm, MPI_Info info,
    MPI_Request *request);
int MPI_Gatherv_init_c (...);