// extern int(*gather)(const void *send_buff, int send_count, MPI_Datatype send_type, void *recv_buff, int recv_count,
// MPI_Datatype recv_type, int root, MPI_Comm comm);
COLL_APPLY(COLL_DEFS, COLL_GATHER_SIG, "")
// extern int(*gather)(const void *send_buff, int send_count, MPI_Datatype send_type, void *recv_buff, int recv_count,
// MPI_Datatype recv_type, int root, MPI_Comm comm);
COLL_APPLY(COLL_DEFS, COLL_GATHER_SIG, "")