---
title: kpccl_shm_comm_size
description: "获取kpccl comm通信域大小。"
url: https://www.hikunpeng.com/document/detail/zh/hpchistory/hpckit/develop2400/KunoengHPCKit_developer_057.html
sourcePath: /source/zh/hpchistory/hpckit/develop2400/KunoengHPCKit_developer_057.html
indexId: c0d15a9d65c2b26327444bf33b8c3be07aefca4eaf5c81125aafc4f69d74d95573
---
# kpccl_shm_comm_size

获取kpccl comm通信域大小。

#### 接口定义

int kpccl_shm_comm_size(kpccl_shm_comm_h comm, int *size);


#### 参数


**表1 参数定义**

| 参数名 | 类型 | 描述 | 输入/输出 |
| --- | --- | --- | --- |
| comm | kpccl\_shm\_comm\_h | kpccl通信域 | 输入 |
| size | int \* | 需要获取的kpccl通信域大小 | 输出 |


#### 返回值

- 成功：返回KPCCL_OK
- 失败：返回KPCCL_ERROR


#### 示例

```
#include <stdio.h>
#include <mpi.h>
#include "kpccl.h"
int oob_allgather_callback(const void *sendbuf, void *recvbuf, int size, void *group，kpccl_shm_datatype_t datatype)
{
switch (datatype) {
case KPCCL_SHM_DATATYPE_CHAR:
return MPI_Allgather(sendbuf, size, MPI_CHAR, recvbuf, size, MPI_CHAR, (MPI_Comm)group);
case KPCCL_SHM_DATATYPE_INT:
return MPI_Allgather(sendbuf, size, MPI_INT, recvbuf, size, MPI_INT, (MPI_Comm)group);
case KPCCL_SHM_DATATYPE_LONG:
return MPI_Allgather(sendbuf, size, MPI_LONG, recvbuf, size, MPI_LONG, (MPI_Comm)group);
case KPCCL_SHM_DATATYPE_FLOAT:
return MPI_Allgather(sendbuf, size, MPI_FLOAT, recvbuf, size, MPI_FLOAT, (MPI_Comm)group);
case KPCCL_SHM_DATATYPE_DOUBLE:
return MPI_Allgather(sendbuf, size, MPI_DOUBLE, recvbuf, size, MPI_DOUBLE, (MPI_Comm)group);
default:
kpccl_error("not support datatype");
return KPCCL_ERROR;
}
}
int
oob_barrier_callback(
void
*
group)
{
return MPI_Barrier((MPI_Comm)group);
}
int main()
{
int myid, numprocs;
MPI_Comm comm = MPI_COMM_WORLD;
MPI_Comm_size(comm, &numprocs);
MPI_Comm_rank(comm, &myid);
kpccl_shm_oob_cb_t oob_cbs;
kpccl_shm_oob_cb_h oob_cbs_h = &oob_cbs;
oob_cbs_h->oob_allgather = oob_allgather_callback;
oob_cbs_h->oob_barrier = oob_barrier_callback;
kpccl_shm_comm_h kpccl_comm;
kpccl_shm_comm_create(numprocs, myid, myid, oob_cbs_h , (void *)comm, &kpccl_comm);
int kpccl_rank, kpccl_size;
kpccl_shm_comm_rank(kpccl_comm, &kpccl_rank);
kpccl_shm_comm_size
(kpccl_comm, &kpccl_size);
kpccl_shm_comm_destroy(kpccl_comm);
}
```

上述示例演示了创建、清理一个kpccl comm的流程。kpccl_shm_comm_size函数获取kpccl comm的size。